title
CS50 2021 in HDR - Lecture 0 - Scratch

description
This is CS50, Harvard University's Introduction to the intellectual enterprises of computer science and the art of programming. Enroll for free at https://cs50.edx.org/. Slides, source code, and more at https://cs50.harvard.edu/x. Playlist at https://www.youtube.com/playlist?list=PLhQjrBD2T383f9scHRNYJkior2VvYjpSL. TABLE OF CONTENTS 00:00:00 - Intro 00:01:17 - Problem Solving 00:05:36 - Representation 00:06:14 - Binary 00:13:25 - Letters 00:16:40 - ASCII 00:20:12 - Unicode 00:25:38 - Color 00:28:00 - Images 00:29:28 - Videos 00:30:43 - Music 00:31:50 - Questions on representation 00:35:41 - Algorithms 00:40:33 - Time to solve 00:43:57 - Pseudocode 00:50:35 - Scratch 00:52:39 - Scratch blocks 00:57:22 - Hello world 01:03:30 - Inputs to outputs, outputs to inputs 01:05:50 - Text to speech 01:07:41 - Meow 01:08:35 - Loops 01:10:42 - Custom blocks 01:15:50 - Conditionals 01:17:25 - Forever 01:18:42 - Video sensing 01:20:25 - Whack-a-mole 01:21:57 - One piece at a time 01:22:48 - Oscartime 01:24:24 - Oscartime stage 01:25:30 - Oscartime trash can 01:27:18 - Oscartime falling trash 01:29:42 - Oscartime dragging trash 01:31:30 - Putting Oscartime together 01:33:42 - Movement 01:35:32 - Movement's abstractions 01:37:30 - Bouncing 01:39:05 - Following 01:41:00 - Ivy's Hardest Game *** This is CS50, Harvard University's introduction to the intellectual enterprises of computer science and the art of programming. *** HOW TO SUBSCRIBE http://www.youtube.com/subscription_center?add_user=cs50tv HOW TO TAKE CS50 edX: https://cs50.edx.org/ Harvard Extension School: https://cs50.harvard.edu/extension Harvard Summer School: https://cs50.harvard.edu/summer OpenCourseWare: https://cs50.harvard.edu/x HOW TO JOIN CS50 COMMUNITIES Discord: https://discord.gg/cs50 Ed: https://cs50.harvard.edu/x/ed Facebook Group: https://www.facebook.com/groups/cs50/ Faceboook Page: https://www.facebook.com/cs50/ GitHub: https://github.com/cs50 Gitter: https://gitter.im/cs50/x Instagram: https://instagram.com/cs50 LinkedIn Group: https://www.linkedin.com/groups/7437240/ LinkedIn Page: https://www.linkedin.com/school/cs50/ Medium: https://cs50.medium.com/ Quora: https://www.quora.com/topic/CS50 Reddit: https://www.reddit.com/r/cs50/ Slack: https://cs50.edx.org/slack Snapchat: https://www.snapchat.com/add/cs50 SoundCloud: https://soundcloud.com/cs50 Stack Exchange: https://cs50.stackexchange.com/ TikTok: https://www.tiktok.com/@cs50 Twitter: https://twitter.com/cs50 YouTube: http://www.youtube.com/cs50 HOW TO FOLLOW DAVID J. MALAN Facebook: https://www.facebook.com/dmalan GitHub: https://github.com/dmalan Instagram: https://www.instagram.com/davidjmalan/ LinkedIn: https://www.linkedin.com/in/malan/ Quora: https://www.quora.com/profile/David-J-Malan TikTok: https://www.tiktok.com/@davidjmalan Twitter: https://twitter.com/davidjmalan *** CS50 SHOP https://cs50.harvardshop.com/ *** LICENSE CC BY-NC-SA 4.0 Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Public License https://creativecommons.org/licenses/by-nc-sa/4.0/ David J. Malan https://cs.harvard.edu/malan malan@harvard.edu

detail
{'title': 'CS50 2021 in HDR - Lecture 0 - Scratch', 'heatmap': [{'end': 5184.118, 'start': 5113.812, 'weight': 1}], 'summary': 'Cs50 lecture discusses programming basics, ascii, unicode, digital info representation, multimedia containers, algorithm efficiency, pseudo code, scratch, interactive coding, game development, emphasizing problem-solving, algorithmic efficiency, and practical programming concepts.', 'chapters': [{'end': 215.131, 'segs': [{'end': 162.455, 'src': 'embed', 'start': 124.586, 'weight': 0, 'content': [{'end': 129.908, 'text': 'brian kernahan, allowed me to take the class pass fail initially, and that is what made all the difference.', 'start': 124.586, 'duration': 5.322}, {'end': 135.212, 'text': 'I quickly found that computer science is not just about programming and working in isolation on your computer.', 'start': 130.288, 'duration': 4.924}, {'end': 137.714, 'text': "It's really about problem solving more generally.", 'start': 135.532, 'duration': 2.182}, {'end': 143.877, 'text': 'And there was something about homework frankly that was like actually fun for perhaps the first time in 19 years.', 'start': 138.074, 'duration': 5.803}, {'end': 152.823, 'text': 'And there was something about this ability that I discovered along with all of my classmates to actually create something and bring a computer to life to solve a problem.', 'start': 144.358, 'duration': 8.465}, {'end': 157.208, 'text': "and sort of bring to bear something that I've been using every day but didn't really know how to harness.", 'start': 153.243, 'duration': 3.965}, {'end': 160.833, 'text': "that's been gratifying ever since and definitely challenging and frustrating.", 'start': 157.208, 'duration': 3.625}, {'end': 162.455, 'text': 'like to these to this day.', 'start': 160.833, 'duration': 1.622}], 'summary': 'Computer science class transformed my approach to problem solving and brought gratifying challenges, making homework fun for the first time in 19 years.', 'duration': 37.869, 'max_score': 124.586, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU124586.jpg'}, {'end': 215.131, 'src': 'embed', 'start': 175.368, 'weight': 2, 'content': [{'end': 180.17, 'text': 'than that sense of gratification and pride really when you get something to work and in a class like this,', 'start': 175.368, 'duration': 4.802}, {'end': 184.513, 'text': 'present ultimately a terms and something like your very own final project.', 'start': 180.17, 'duration': 4.343}, {'end': 188.074, 'text': "Now this isn't to say that I took to it 100% perfectly.", 'start': 184.893, 'duration': 3.181}, {'end': 189.714, 'text': 'In fact just this.', 'start': 188.114, 'duration': 1.6}, {'end': 195.256, 'text': 'this past week I looked in my old CS 50 binder, which I still have from some 25 years ago,', 'start': 189.714, 'duration': 5.542}, {'end': 202.718, 'text': 'and took a photo of what was apparently the very first program that I wrote and submitted and quickly received minus two points on.', 'start': 195.256, 'duration': 7.462}, {'end': 210.967, 'text': 'But this is a program that will soon see in the coming days that does something quite simply like print hello CS 50 in this case to the screen.', 'start': 203.058, 'duration': 7.909}, {'end': 215.131, 'text': "And to be fair, I technically hadn't really followed the directions, which is why I lost those couple of points.", 'start': 211.287, 'duration': 3.844}], 'summary': 'Struggled with first program in cs 50, lost two points for not following directions.', 'duration': 39.763, 'max_score': 175.368, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU175368.jpg'}], 'start': 11.307, 'title': 'Cs50 and final project reflection', 'summary': "Introduces cs50, emphasizing problem-solving and programming satisfaction, and reflects on the sense of gratification and pride in completing a final project, citing a personal example from 25 years ago and the initial setback faced with a simple 'hello cs 50' program.", 'chapters': [{'end': 175.368, 'start': 11.307, 'title': 'Cs50 intro to computer science', 'summary': "Introduces cs50, harvard university's introduction to computer science, emphasizing the value of problem-solving in computer science and the satisfaction of creating and solving problems with programming.", 'duration': 164.061, 'highlights': ['Computer science is not just about programming, but about problem-solving more generally, which can be fun and gratifying (e.g. homework was fun for the first time in 19 years).', 'The ability to create something and bring a computer to life to solve a problem is discovered, which is challenging, frustrating, and gratifying (e.g. dealing with bugs and taking breaks).', 'The professor allowing the speaker to initially take the class pass fail made all the difference in deciding to take the class.']}, {'end': 215.131, 'start': 175.368, 'title': 'Cs 50 final project reflection', 'summary': "Reflects on the sense of gratification and pride in completing a final project, citing a personal example from 25 years ago and the initial setback faced with a simple 'hello cs 50' program.", 'duration': 39.763, 'highlights': ['The speaker reflects on the sense of gratification and pride in completing a final project, emphasizing the personal experience (25 years ago) and the significance of submitting a very own final project in a class like CS 50.', "The speaker shares a personal anecdote of receiving minus two points for the very first program submitted, which was a simple 'hello CS 50' print to the screen, highlighting the initial setback faced in following the directions accurately.", 'The speaker emphasizes the significance of a final project in a class like CS 50, highlighting the sense of gratification and pride upon successfully completing it.']}], 'duration': 203.824, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU11307.jpg', 'highlights': ['The ability to create something and bring a computer to life to solve a problem is challenging, frustrating, and gratifying (e.g. dealing with bugs and taking breaks).', 'Computer science is not just about programming, but about problem-solving more generally, which can be fun and gratifying (e.g. homework was fun for the first time in 19 years).', 'The speaker reflects on the sense of gratification and pride in completing a final project, emphasizing the personal experience (25 years ago) and the significance of submitting a very own final project in a class like CS 50.', 'The speaker emphasizes the significance of a final project in a class like CS 50, highlighting the sense of gratification and pride upon successfully completing it.', 'The professor allowing the speaker to initially take the class pass fail made all the difference in deciding to take the class.', "The speaker shares a personal anecdote of receiving minus two points for the very first program submitted, which was a simple 'hello CS 50' print to the screen, highlighting the initial setback faced in following the directions accurately."]}, {'end': 974.526, 'segs': [{'end': 289.453, 'src': 'embed', 'start': 231.968, 'weight': 0, 'content': [{'end': 237.413, 'text': "Once you start to wrap your mind around what it is and how it works and what these various languages are, it's so easy.", 'start': 231.968, 'duration': 5.445}, {'end': 239.636, 'text': "You'll see after a few months of a class like this,", 'start': 237.433, 'duration': 2.203}, {'end': 244.981, 'text': 'to start teaching yourself subsequently other languages as they may come in the coming years as well.', 'start': 239.636, 'duration': 5.345}, {'end': 251.484, 'text': 'So what ultimately matters in this particular course is not so much where you end up relative to your classmates,', 'start': 245.561, 'duration': 5.923}, {'end': 255.967, 'text': "but where you end up relative to yourself when you began and indeed you'll begin today,", 'start': 251.484, 'duration': 4.483}, {'end': 259.488, 'text': 'and the only experience that matters ultimately in this class is your own.', 'start': 255.967, 'duration': 3.521}, {'end': 261.47, 'text': 'And so consider where you are today.', 'start': 259.649, 'duration': 1.821}, {'end': 268.253, 'text': 'Consider perhaps just how cryptic something like that looked a few seconds ago and take comfort in knowing, just some months from now,', 'start': 261.81, 'duration': 6.443}, {'end': 271.376, 'text': 'all of that will be within your own grasp.', 'start': 268.253, 'duration': 3.123}, {'end': 276.08, 'text': "And if you're thinking that surely the person in front of me to the left to the right behind me knows more than me.", 'start': 271.416, 'duration': 4.664}, {'end': 277.802, 'text': "That's statistically not the case.", 'start': 276.12, 'duration': 1.682}, {'end': 286.61, 'text': "Two thirds of CS 50 students have never taken a CS course before, which is to say you're in very good company throughout this whole term.", 'start': 278.262, 'duration': 8.348}, {'end': 289.453, 'text': 'So then, what is computer science?', 'start': 287.592, 'duration': 1.861}], 'summary': 'Cs 50 course enables self-learning of multiple languages, with majority being new to cs.', 'duration': 57.485, 'max_score': 231.968, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU231968.jpg'}, {'end': 383.38, 'src': 'embed', 'start': 359.437, 'weight': 1, 'content': [{'end': 367.586, 'text': 'Assembly one, but binary two might be your go to, and binary by implying two means that the world of computers has just two digits at its disposal,', 'start': 359.437, 'duration': 8.149}, {'end': 371.831, 'text': 'zero and one, and indeed we humans have many more than that.', 'start': 367.586, 'duration': 4.245}, {'end': 377.898, 'text': 'Certainly not just zeros and ones alone but a computer indeed only has zeros and ones and yet somehow they can do so much.', 'start': 371.891, 'duration': 6.007}, {'end': 383.38, 'text': 'They can crunch numbers in excels and text messages, create images and and artwork and movies and more.', 'start': 377.998, 'duration': 5.382}], 'summary': 'Computers operate with binary system using only zeros and ones, yet they can perform a wide range of tasks including crunching numbers, creating images, artwork, and movies.', 'duration': 23.943, 'max_score': 359.437, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU359437.jpg'}, {'end': 492.768, 'src': 'embed', 'start': 472.351, 'weight': 4, 'content': [{'end': 483.02, 'text': "And then, if we want four or five or six or seven, we're just kind of toggling these zeros and ones, aka bits for binary digits, that represent,", 'start': 472.351, 'duration': 10.669}, {'end': 489.785, 'text': 'by these different patterns, different numbers that you and I, as humans, know of course as the so called decimal system zero through nine deck,', 'start': 483.02, 'duration': 6.765}, {'end': 492.768, 'text': 'implying 10, 10 digits, those zeros through nine.', 'start': 489.785, 'duration': 2.983}], 'summary': 'Toggling binary digits to represent numbers in the decimal system.', 'duration': 20.417, 'max_score': 472.351, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU472351.jpg'}], 'start': 215.171, 'title': 'Programming language basics and computer science', 'summary': 'Discusses the challenges of programming and mastering it, leading to learning other languages. it also introduces computer science as problem solving, emphasizing the significance of binary representation in computers, explained through counting and mapping of letters to numbers.', 'chapters': [{'end': 271.376, 'start': 215.171, 'title': 'Programming language basics', 'summary': "Discusses the initial challenges of programming, emphasizing that understanding and mastering it will be easier with time, leading to the ability to learn other languages, highlighting the individual's progress over comparison with peers.", 'duration': 56.205, 'highlights': ['Understanding programming becomes easier with time, enabling individuals to learn other languages as well.', 'Emphasizing the importance of individual progress over comparison with peers.', 'Highlighting the initial challenge of the cryptic appearance of programming, which will become more understandable in a few months.']}, {'end': 974.526, 'start': 271.416, 'title': 'Computer science: problem solving and binary representation', 'summary': 'Introduces computer science as problem solving, emphasizing the significance of binary representation in computers, which is explained through a detailed discussion of counting, binary representation, and the mapping of letters to numbers in computer systems.', 'duration': 703.11, 'highlights': ['Computer science is problem solving and learning to program, which fosters methodical and precise thinking, with two-thirds of CS50 students never having taken a CS course before.', 'Computers primarily use binary with two digits, 0 and 1, to represent data and perform various tasks like counting, where binary patterns represent different numbers.', 'Binary representation follows a pattern similar to the decimal system, with columns representing powers of 2, and the mapping of letters to numbers in computers involves standardized patterns of zeros and ones.']}], 'duration': 759.355, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU215171.jpg', 'highlights': ['Computer science fosters methodical and precise thinking, with two-thirds of CS50 students never having taken a CS course before.', 'Computers primarily use binary with two digits, 0 and 1, to represent data and perform various tasks like counting.', 'Understanding programming becomes easier with time, enabling individuals to learn other languages as well.', 'Emphasizing the importance of individual progress over comparison with peers.', 'Binary representation follows a pattern similar to the decimal system, with columns representing powers of 2.']}, {'end': 1385.997, 'segs': [{'end': 1015.451, 'src': 'embed', 'start': 975.066, 'weight': 2, 'content': [{'end': 983.848, 'text': 'We shall interpret any patterns of zeros and ones as being maybe numbers for excel, maybe letters in, like a text messaging program, or google docs,', 'start': 975.066, 'duration': 8.782}, {'end': 987.108, 'text': 'or maybe even colors of the rainbow and something like photoshop and more.', 'start': 983.848, 'duration': 3.26}, {'end': 991.549, 'text': "So it's context dependent and we'll see when we ourselves start programming you.", 'start': 987.148, 'duration': 4.401}, {'end': 994.31, 'text': 'the programmer will ultimately provide some hints to the computer.', 'start': 991.549, 'duration': 2.761}, {'end': 996.512, 'text': 'that tells the computer.', 'start': 994.85, 'duration': 1.662}, {'end': 998.173, 'text': 'interpret it as follows', 'start': 996.512, 'duration': 1.661}, {'end': 1001.897, 'text': 'So similar in spirit to that but not quite as standardized with these prefixes.', 'start': 998.274, 'duration': 3.623}, {'end': 1008.985, 'text': 'So this system here actually has a name asking the american standard code for information interchange and indeed it began here in the U.', 'start': 1001.957, 'duration': 7.028}, {'end': 1013.589, 'text': "S And that's why it's actually a little biased toward A's through Z's and a bit of punctuation as well.", 'start': 1008.985, 'duration': 4.604}, {'end': 1015.451, 'text': 'And that quickly became a problem.', 'start': 1014.01, 'duration': 1.441}], 'summary': 'Interpreting zeros and ones as numbers, letters, or colors, the american standard code for information interchange (ascii) is context-dependent and biased towards a-z and punctuation. it quickly became a problem.', 'duration': 40.385, 'max_score': 975.066, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU975066.jpg'}, {'end': 1133.559, 'src': 'embed', 'start': 1104.577, 'weight': 0, 'content': [{'end': 1110.862, 'text': "But it's important to note that when you get these patterns of zeros and ones in any format, be it email or text or a file,", 'start': 1104.577, 'duration': 6.285}, {'end': 1113.024, 'text': 'they do tend to come in standard lengths.', 'start': 1110.862, 'duration': 2.162}, {'end': 1116.766, 'text': 'with a certain number of zeros and ones altogether.', 'start': 1113.484, 'duration': 3.282}, {'end': 1119.629, 'text': 'And this happens to be eight plus eight plus eight.', 'start': 1117.127, 'duration': 2.502}, {'end': 1127.074, 'text': 'So just to get the message high exclamation point, you would have received at least it would seem some 24 bits.', 'start': 1120.069, 'duration': 7.005}, {'end': 1133.559, 'text': "But frankly, bits are so tiny literally and mathematically that we don't tend to think or talk generally in terms of bits.", 'start': 1127.835, 'duration': 5.724}], 'summary': 'Zeros and ones tend to come in standard lengths, 24 bits for high exclamation message.', 'duration': 28.982, 'max_score': 1104.577, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1104577.jpg'}, {'end': 1295.655, 'src': 'embed', 'start': 1253.392, 'weight': 1, 'content': [{'end': 1260.214, 'text': 'For instance, there are certain emojis that were represented with certain patterns of bits, and when you receive them, your phone, your laptop,', 'start': 1253.392, 'duration': 6.822}, {'end': 1265.096, 'text': 'your desktop displays them as such, and this newer standard is called Unicode.', 'start': 1260.214, 'duration': 4.882}, {'end': 1273.44, 'text': "So it's a superset of what we called ASCII, and Unicode is just a mapping of many more numbers to many more letters or characters.", 'start': 1265.656, 'duration': 7.784}, {'end': 1279.743, 'text': 'more generally, that might use eight bits for backwards compatibility with the old way of doing things with ASCII.', 'start': 1273.44, 'duration': 6.303}, {'end': 1281.424, 'text': 'But they might also use 16 bits.', 'start': 1280.184, 'duration': 1.24}, {'end': 1288.309, 'text': "And if you have 16 bits, you can actually represent more than 65, 000 possible letters and that's getting up there.", 'start': 1282.665, 'duration': 5.644}, {'end': 1295.655, 'text': 'And heck Unicode might even use 32 bits to represent letters and numbers and punctuation symbols and emojis.', 'start': 1288.689, 'duration': 6.966}], 'summary': 'Unicode is a superset of ascii, using 16 bits to represent over 65,000 characters and possibly 32 bits for emojis.', 'duration': 42.263, 'max_score': 1253.392, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1253392.jpg'}], 'start': 975.066, 'title': 'Ascii and unicode representation', 'summary': "Explains the interpretation of zeros and ones as numbers, letters, or colors using ascii, bias towards a's through z's and punctuation, and discusses the mapping of characters to numbers in ascii and unicode, standard lengths of patterns of zeros and ones, and the use of bits and bytes to represent characters and data.", 'chapters': [{'end': 1015.451, 'start': 975.066, 'title': 'Ascii interpretation', 'summary': "Explains how patterns of zeros and ones can be interpreted as numbers, letters, or colors, and introduces the american standard code for information interchange (ascii) as a system that started in the u.s. and is biased towards a's through z's and punctuation.", 'duration': 40.385, 'highlights': ["The American Standard Code for Information Interchange (ASCII) began in the U.S and is biased towards A's through Z's and punctuation.", 'Patterns of zeros and ones can be interpreted as numbers, letters, or colors in different contexts.', 'The programmer provides hints to the computer for interpretation.']}, {'end': 1385.997, 'start': 1015.551, 'title': 'Understanding ascii and unicode', 'summary': 'Discusses the mapping of characters to numbers in ascii and unicode, the standard lengths of patterns of zeros and ones, and the use of bits and bytes to represent characters and data, including the implications for representing human languages and emojis.', 'duration': 370.446, 'highlights': ['The chapter explains the mapping of characters to numbers in ASCII and Unicode, with ASCII using 8 bits and Unicode using 16 or 32 bits to represent characters, allowing for the representation of more letters, numbers, punctuation symbols, and emojis.', 'The standard lengths of patterns of zeros and ones are discussed, with the chapter explaining that patterns of zeros and ones tend to come in standard lengths, such as 8 bits for a byte, and the implications of this for representing characters and data.', 'The implications of using bits and bytes to represent characters and data are explored, including the limitations of representing human languages and the use of bits and bytes to represent emojis, with Unicode being a superset of ASCII.']}], 'duration': 410.931, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU975066.jpg', 'highlights': ['The standard lengths of patterns of zeros and ones are discussed, with the chapter explaining that patterns of zeros and ones tend to come in standard lengths, such as 8 bits for a byte, and the implications of this for representing characters and data.', 'The chapter explains the mapping of characters to numbers in ASCII and Unicode, with ASCII using 8 bits and Unicode using 16 or 32 bits to represent characters, allowing for the representation of more letters, numbers, punctuation symbols, and emojis.', "The American Standard Code for Information Interchange (ASCII) began in the U.S and is biased towards A's through Z's and punctuation.", 'Patterns of zeros and ones can be interpreted as numbers, letters, or colors in different contexts.', 'The implications of using bits and bytes to represent characters and data are explored, including the limitations of representing human languages and the use of bits and bytes to represent emojis, with Unicode being a superset of ASCII.', 'The programmer provides hints to the computer for interpretation.']}, {'end': 2026.796, 'segs': [{'end': 1438.705, 'src': 'embed', 'start': 1416.52, 'weight': 0, 'content': [{'end': 1426.653, 'text': 'Binary is one, decimal is another, unary is another and hexadecimal is yet a fourth that uses 16 total digits, literally zero through nine plus a, b,', 'start': 1416.52, 'duration': 10.133}, {'end': 1427.694, 'text': 'c, d, e, f.', 'start': 1426.653, 'duration': 1.041}, {'end': 1430.557, 'text': 'And somehow you can similarly count even higher with those.', 'start': 1427.694, 'duration': 2.863}, {'end': 1433.6, 'text': "We'll see in a few weeks why this is compelling.", 'start': 1431.238, 'duration': 2.362}, {'end': 1437.263, 'text': 'But hexadecimal long story short uses four bits per digit.', 'start': 1433.88, 'duration': 3.383}, {'end': 1438.705, 'text': 'And so four bits.', 'start': 1437.644, 'duration': 1.061}], 'summary': 'Hexadecimal uses 16 total digits, and four bits per digit.', 'duration': 22.185, 'max_score': 1416.52, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1416520.jpg'}, {'end': 1682.418, 'src': 'embed', 'start': 1654.691, 'weight': 1, 'content': [{'end': 1658.376, 'text': 'You can think of the first digit is red, second is green, third as blue.', 'start': 1654.691, 'duration': 3.685}, {'end': 1663.523, 'text': 'And so, ultimately, when you combine that amount of red, that amount of green, that amount of blue,', 'start': 1658.436, 'duration': 5.087}, {'end': 1671.81, 'text': "it turns out it's going to resemble this shade of yellow, and indeed you can come up with numbers between zero and 255 for each of those colors,", 'start': 1663.523, 'duration': 8.287}, {'end': 1673.932, 'text': 'to mix any other color that you might want.', 'start': 1671.81, 'duration': 2.122}, {'end': 1680.496, 'text': 'And you can actually see this in practice, even though our screens, admittedly, are getting really good on our phones and laptops,', 'start': 1674.212, 'duration': 6.284}, {'end': 1682.418, 'text': 'such that you barely see the dots.', 'start': 1680.496, 'duration': 1.922}], 'summary': 'Combining red, green, and blue in varying amounts creates a range of colors with values between zero and 255.', 'duration': 27.727, 'max_score': 1654.691, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1654691.jpg'}, {'end': 1873.482, 'src': 'embed', 'start': 1840.202, 'weight': 4, 'content': [{'end': 1842.763, 'text': "because they're just this grid of these pixels or dots.", 'start': 1840.202, 'duration': 2.561}, {'end': 1848.786, 'text': 'Now something like musical notes like these, those of you who are musicians might just naturally play these on physical devices.', 'start': 1843.163, 'duration': 5.623}, {'end': 1851.707, 'text': 'But computers can certainly represent those sounds too.', 'start': 1848.826, 'duration': 2.881}, {'end': 1859.411, 'text': 'And, for instance, a popular format for audio is called midi, and midi might just represent each note that you saw a moment ago,', 'start': 1851.747, 'duration': 7.664}, {'end': 1861.552, 'text': 'essentially as a sequence of numbers.', 'start': 1859.411, 'duration': 2.141}, {'end': 1867.537, 'text': 'But more generally you might think about music as having notes for instance A through G maybe some flats and some sharps.', 'start': 1861.892, 'duration': 5.645}, {'end': 1873.482, 'text': 'You might have the duration like how long is the note being heard or played on a piano or some other device?', 'start': 1868.077, 'duration': 5.405}], 'summary': 'Computers can represent musical notes as midi, a sequence of numbers, with specific note names and durations.', 'duration': 33.28, 'max_score': 1840.202, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1840202.jpg'}, {'end': 1976.829, 'src': 'embed', 'start': 1954.208, 'weight': 3, 'content': [{'end': 1961.618, 'text': "It's not quite as simple when using larger files for instance in more modern formats that a video is just a sequence of images for instance.", 'start': 1954.208, 'duration': 7.41}, {'end': 1969.964, 'text': "Why? If you stored that many images for like a Hollywood movie like 24 or 30 of them per second, that's a huge number of images.", 'start': 1961.658, 'duration': 8.306}, {'end': 1976.829, 'text': "And if you've ever taken phone photos on your phone, you might know how many megabytes or larger even individual photographs might be.", 'start': 1970.004, 'duration': 6.825}], 'summary': 'Storing hollywood movie images can create huge file sizes, as seen with phone photos.', 'duration': 22.621, 'max_score': 1954.208, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1954208.jpg'}, {'end': 2024.435, 'src': 'embed', 'start': 1990.778, 'weight': 5, 'content': [{'end': 1992.639, 'text': 'And they use what might be called compression.', 'start': 1990.778, 'duration': 1.861}, {'end': 1999.803, 'text': "If you've ever used a zip file or something else, somehow your computer is using fewer zeros and ones to represent the same amount of information,", 'start': 1992.919, 'duration': 6.884}, {'end': 2001.884, 'text': 'ideally without losing any information.', 'start': 1999.803, 'duration': 2.081}, {'end': 2008.948, 'text': 'And in the world of multimedia, which will touch on a little bit in a few weeks, there are both lossy and lossless formats out there.', 'start': 2002.264, 'duration': 6.684}, {'end': 2012.37, 'text': 'Lossless means you lose no information whatsoever.', 'start': 2009.008, 'duration': 3.362}, {'end': 2017.072, 'text': "But more commonly as you're alluding to one is lossy compression L.", 'start': 2012.75, 'duration': 4.322}, {'end': 2017.453, 'text': 'O S.', 'start': 2017.072, 'duration': 0.381}, {'end': 2018.113, 'text': 'S Y.', 'start': 2017.453, 'duration': 0.66}, {'end': 2024.435, 'text': "Where you're actually throwing away some amount of quality, you're getting some amount of pixelation that might not look perfect to the human.", 'start': 2018.113, 'duration': 6.322}], 'summary': 'Compression reduces file size with lossy or lossless methods.', 'duration': 33.657, 'max_score': 1990.778, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1990778.jpg'}], 'start': 1386.437, 'title': 'Digital information representation', 'summary': 'Discusses representing information with zeros and ones, using hexadecimal numbers and the rgb color model. it also covers how digital devices represent images, videos, and audio through compression and file formats.', 'chapters': [{'end': 1673.932, 'start': 1386.437, 'title': 'Representing information with zeros and ones', 'summary': 'Discusses the representation of information using zeros and ones, including the use of hexadecimal numbers and the rgb color model, where 8 bits can represent 256 total possible patterns of zeros and ones, and colors can be represented using a combination of some amount of red, green, and blue with numbers between zero and 255 for each color.', 'duration': 287.495, 'highlights': ['The use of hexadecimal numbers allows for the representation of 256 total possible patterns of zeros and ones with 8 bits, as each hexadecimal digit uses 4 bits, providing a convenient unit of measure and human convention in representing files and other data.', 'Colors can be represented using the RGB model, with numbers between zero and 255 for each color (red, green, and blue), allowing for the mixing of any color by combining different amounts of red, green, and blue to represent a specific shade.', 'Binary, decimal, unary, and hexadecimal are various ways to represent numbers, with hexadecimal using 16 total digits (0-9, a-f) and providing a compelling way to count higher, using four bits per digit.']}, {'end': 2026.796, 'start': 1674.212, 'title': 'Digital information representation', 'summary': 'Discusses how digital devices represent information using pixels, zeros and ones, representing images, videos, and audio through compression and file formats, and how computers interpret and process these representations.', 'duration': 352.584, 'highlights': ['Computers represent images using pixels composed of 24 bits, and videos as a sequence of images, typically 24 or 30 per second.', 'Audio can be represented as MIDI, with notes being represented as a sequence of numbers, including pitch, duration, and volume.', 'File formats and codecs use compression to represent multimedia information more minimally, with lossy and lossless formats available.']}], 'duration': 640.359, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU1386437.jpg', 'highlights': ['The use of hexadecimal numbers allows for the representation of 256 total possible patterns of zeros and ones with 8 bits, as each hexadecimal digit uses 4 bits, providing a convenient unit of measure and human convention in representing files and other data.', 'Colors can be represented using the RGB model, with numbers between zero and 255 for each color (red, green, and blue), allowing for the mixing of any color by combining different amounts of red, green, and blue to represent a specific shade.', 'Binary, decimal, unary, and hexadecimal are various ways to represent numbers, with hexadecimal using 16 total digits (0-9, a-f) and providing a compelling way to count higher, using four bits per digit.', 'Computers represent images using pixels composed of 24 bits, and videos as a sequence of images, typically 24 or 30 per second.', 'Audio can be represented as MIDI, with notes being represented as a sequence of numbers, including pitch, duration, and volume.', 'File formats and codecs use compression to represent multimedia information more minimally, with lossy and lossless formats available.']}, {'end': 2421.199, 'segs': [{'end': 2092.908, 'src': 'embed', 'start': 2058.108, 'weight': 0, 'content': [{'end': 2065.371, 'text': 'you might have heard of the expression of vacuum tube, which is like some physically large device that might have only stored some zero or one.', 'start': 2058.108, 'duration': 7.263}, {'end': 2074.176, 'text': 'Yes, it is the miniaturization of hardware these days that has allowed us to store as many and many more zeros and ones much more closely together.', 'start': 2066.032, 'duration': 8.144}, {'end': 2078.679, 'text': 'And as we built more fancy machines that can sort of design this hardware at an even smaller scale,', 'start': 2074.235, 'duration': 4.444}, {'end': 2080.84, 'text': "we're just packing more and more into these devices.", 'start': 2078.679, 'duration': 2.161}, {'end': 2082.501, 'text': 'But there too is a trade off.', 'start': 2081.26, 'duration': 1.241}, {'end': 2088.344, 'text': 'For instance, you might know by using your phone, or your laptop for quite a while, maybe on your lap starts to get warm.', 'start': 2082.521, 'duration': 5.823}, {'end': 2092.908, 'text': 'And so there are these literal physical side effects of this where now some of our devices run hot.', 'start': 2088.364, 'duration': 4.544}], 'summary': 'Miniaturization of hardware enables storing more data, but leads to devices running hot.', 'duration': 34.8, 'max_score': 2058.108, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2058108.jpg'}, {'end': 2173.444, 'src': 'embed', 'start': 2150.629, 'weight': 2, 'content': [{'end': 2159.794, 'text': 'When you write software aka programs you are implementing one or more algorithms one or more step sets of instructions for solving some problem.', 'start': 2150.629, 'duration': 9.165}, {'end': 2161.915, 'text': "And maybe you're using this language or that.", 'start': 2160.194, 'duration': 1.721}, {'end': 2169.518, 'text': 'But at the end of the day, no matter the language you use, the computer is going to represent what you type using just zeros and ones.', 'start': 2161.955, 'duration': 7.563}, {'end': 2173.444, 'text': 'So what might be a representative algorithm nowadays??', 'start': 2170.603, 'duration': 2.841}], 'summary': 'Software implementation involves algorithms using zeros and ones.', 'duration': 22.815, 'max_score': 2150.629, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2150629.jpg'}, {'end': 2238.948, 'src': 'embed', 'start': 2210.861, 'weight': 4, 'content': [{'end': 2216.488, 'text': 'in this, physical book might be a whole bunch of names, alphabetically sorted from left to right, corresponding to a whole bunch of numbers.', 'start': 2210.861, 'duration': 5.627}, {'end': 2221.633, 'text': 'So suppose that In this old harvard phone book we want to search for john harvard.', 'start': 2217.089, 'duration': 4.544}, {'end': 2228.579, 'text': 'We might of course start quite simply at the beginning here looking at one page at a time and this is an algorithm.', 'start': 2221.953, 'duration': 6.626}, {'end': 2234.965, 'text': 'This is like literally step by steps looking for the solution to this problem in that sense.', 'start': 2228.639, 'duration': 6.326}, {'end': 2238.948, 'text': "If john harvard's in the phone book is this algorithm page by page? Correct.", 'start': 2235.105, 'duration': 3.843}], 'summary': 'Searching for john harvard in a physical phone book using step-by-step algorithm.', 'duration': 28.087, 'max_score': 2210.861, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2210861.jpg'}, {'end': 2396.688, 'src': 'embed', 'start': 2368.708, 'weight': 3, 'content': [{'end': 2376.132, 'text': "And I think if I repeat this again dividing and conquering if you will here I might have gone a little too far now I'm in like the E section.", 'start': 2368.708, 'duration': 7.424}, {'end': 2384.458, 'text': 'So let me tear the problem in half again, throw another 250 pages away and again repeat, dividing and dividing and conquering until finally,', 'start': 2376.172, 'duration': 8.286}, {'end': 2390.463, 'text': "presumably, I end up with just one page of a phone book on which John Harvard's name either is or is not.", 'start': 2384.458, 'duration': 6.005}, {'end': 2396.688, 'text': "But because of the algorithm you propose step by step, I know that he's not in anything I discarded.", 'start': 2390.944, 'duration': 5.744}], 'summary': "Repeating the divide and conquer method, discarding 250 pages at a time, aiming to find john harvard's name in a phone book.", 'duration': 27.98, 'max_score': 2368.708, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2368708.jpg'}, {'end': 2431.869, 'src': 'embed', 'start': 2406.513, 'weight': 5, 'content': [{'end': 2414.496, 'text': "It's not about learning a completely new world, but really just had a harness intuition and ideas that you might already have and take naturally.", 'start': 2406.513, 'duration': 7.983}, {'end': 2421.199, 'text': 'But learning how to express them now more succinctly, more precisely and using things called programming languages.', 'start': 2414.536, 'duration': 6.663}, {'end': 2431.869, 'text': 'Why is an algorithm like that if I found John Harvard better than ultimately just doing the first one or even the second and maybe doubling back to check those even pages?', 'start': 2421.939, 'duration': 9.93}], 'summary': 'Learn to harness intuition and express ideas succinctly using programming languages and algorithms.', 'duration': 25.356, 'max_score': 2406.513, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2406513.jpg'}], 'start': 2027.417, 'title': 'Multimedia containers, data storage, and phone book search algorithm', 'summary': 'Covers multimedia containers such as quicktime, hardware miniaturization for increased data storage, physical side effects, importance of algorithms, and data representation. it also discusses the inefficiency of linear search, the effectiveness of divide and conquer algorithm, and its connection to programming.', 'chapters': [{'end': 2173.444, 'start': 2027.417, 'title': 'Multimedia containers and data storage', 'summary': 'Discusses multimedia containers like quicktime, the miniaturization of hardware allowing for more data storage, physical side effects of data storage, the importance of algorithms, and the representation of data using zeros and ones.', 'duration': 146.027, 'highlights': ['The miniaturization of hardware these days has allowed us to store as many and many more zeros and ones much more closely together.', 'There are these literal physical side effects of this where now some of our devices run hot.', 'When you write software aka programs you are implementing one or more algorithms one or more step sets of instructions for solving some problem.', 'You might know by using your phone, or your laptop for quite a while, maybe on your lap starts to get warm.']}, {'end': 2421.199, 'start': 2173.484, 'title': 'Phone book search algorithm', 'summary': 'Discusses the search algorithm for a phone book, illustrating the inefficiency of linear search and the effectiveness of the divide and conquer algorithm, showcasing how it reduces the search space by half at each step and harnesses human intuition, connecting it to the concept of programming.', 'duration': 247.715, 'highlights': ['The divide and conquer algorithm for searching phone books reduces the search space by half at each step, leading to a more efficient search process.', 'The inefficiency of linear search is demonstrated through the example of searching for a name in a physical phone book, where the linear search would take a long time to find the desired name.', 'The discussion emphasizes the importance of harnessing human intuition in programming, illustrating how programming is about expressing natural ideas more succinctly and precisely using programming languages.']}], 'duration': 393.782, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2027417.jpg', 'highlights': ['The miniaturization of hardware allows for increased data storage.', 'The physical side effects of hardware miniaturization include devices running hot.', 'Algorithms are step sets of instructions for solving problems in software.', 'The divide and conquer algorithm reduces search space by half for more efficient search.', 'Linear search is inefficient, demonstrated through the example of searching a physical phone book.', 'Programming involves expressing natural ideas more succinctly and precisely using programming languages.']}, {'end': 2886.511, 'segs': [{'end': 2498.435, 'src': 'embed', 'start': 2464.155, 'weight': 1, 'content': [{'end': 2464.916, 'text': 'No matter the slope.', 'start': 2464.155, 'duration': 0.761}, {'end': 2472.965, 'text': "it's a straight line, because there's presumably a one to one relationship between numbers of pages and number of seconds or number of page turns.", 'start': 2464.916, 'duration': 8.049}, {'end': 2480.815, 'text': "Why?? If the phone company adds another page next year because some new people move to town, that's going to require one additional page for me, one to one.", 'start': 2473.146, 'duration': 7.669}, {'end': 2489.946, 'text': "If, though, we use the second algorithm flawed though it was, unless we double back a little bit to fix someone being in between, that's, too,", 'start': 2481.937, 'duration': 8.009}, {'end': 2496.653, 'text': "going to be a straight line, but it's going to be a different slope, because now there's a two to one or a one to two relationship,", 'start': 2489.946, 'duration': 6.707}, {'end': 2498.435, 'text': "because I'm going two pages at a time.", 'start': 2496.653, 'duration': 1.782}], 'summary': 'The relationship between pages and time creates a straight line with a one-to-one or two-to-one ratio, depending on the algorithm used.', 'duration': 34.28, 'max_score': 2464.155, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2464155.jpg'}, {'end': 2564.399, 'src': 'embed', 'start': 2536.055, 'weight': 0, 'content': [{'end': 2538.798, 'text': "and over to half as many, because you're going twice as fast.", 'start': 2536.055, 'duration': 2.743}, {'end': 2544.663, 'text': 'But the third algorithm actually if you recall your your logarithms looks a little something like this.', 'start': 2538.858, 'duration': 5.805}, {'end': 2550.688, 'text': "There's a fundamentally different relationship between the size of the problem and the amount of time required to solve it.", 'start': 2545.124, 'duration': 5.564}, {'end': 2552.81, 'text': 'That technically is log base to event.', 'start': 2551.048, 'duration': 1.762}, {'end': 2554.711, 'text': "But it's really the shape that's different.", 'start': 2552.83, 'duration': 1.881}, {'end': 2560.516, 'text': 'And the implication there is that If, for instance, Cambridge and Alston, two different towns here in Massachusetts,', 'start': 2555.472, 'duration': 5.044}, {'end': 2564.399, 'text': "merged next year and there's just one phone book, that's twice as big.", 'start': 2560.516, 'duration': 3.883}], 'summary': 'Logarithm algorithm allows solving problems with half the time and double the size.', 'duration': 28.344, 'max_score': 2536.055, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2536055.jpg'}, {'end': 2826.729, 'src': 'embed', 'start': 2795.562, 'weight': 3, 'content': [{'end': 2800.883, 'text': "But you'll get better at thinking about those corner cases and handling anything that can possibly go wrong.", 'start': 2795.562, 'duration': 5.321}, {'end': 2803.844, 'text': 'And as a result, your code will be all the better for it.', 'start': 2800.903, 'duration': 2.941}, {'end': 2807.986, 'text': 'Now the problem, ultimately with learning how to program,', 'start': 2804.645, 'duration': 3.341}, {'end': 2814.287, 'text': "especially if you've never had experience or even if you do but you learned a one language only,", 'start': 2807.986, 'duration': 6.301}, {'end': 2819.788, 'text': 'is that they all look a little cryptic at first glance, but they do share certain commonalities.', 'start': 2814.287, 'duration': 5.501}, {'end': 2826.729, 'text': "In fact, we'll use this pseudo code to define those first highlighted in yellow here or what henceforth we're going to start calling functions.", 'start': 2819.828, 'duration': 6.901}], 'summary': 'Learning to program improves problem-solving and code quality.', 'duration': 31.167, 'max_score': 2795.562, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2795562.jpg'}, {'end': 2886.511, 'src': 'embed', 'start': 2832.45, 'weight': 4, 'content': [{'end': 2836.371, 'text': 'which are actions or verbs that solve some smaller problem.', 'start': 2832.45, 'duration': 3.921}, {'end': 2841.593, 'text': 'That is to say, you might use a whole bunch of functions to solve a bigger problem, because each functions tend to do.', 'start': 2836.812, 'duration': 4.781}, {'end': 2845.094, 'text': 'each function tends to do something very specific or precise.', 'start': 2841.593, 'duration': 3.501}, {'end': 2853.016, 'text': 'These then in english might be translated in code, actual computer code to these things called functions highlighted in yellow.', 'start': 2845.694, 'duration': 7.322}, {'end': 2855.197, 'text': 'now are what we might call conditionals.', 'start': 2853.016, 'duration': 2.181}, {'end': 2859.999, 'text': 'conditionals are things that you do conditionally based on the answer to some question.', 'start': 2855.737, 'duration': 4.262}, {'end': 2862.239, 'text': 'You can think of them kind of like forks in the road.', 'start': 2860.359, 'duration': 1.88}, {'end': 2867.401, 'text': 'You go left or go right or some other direction based on the answer to some question.', 'start': 2862.319, 'duration': 5.082}, {'end': 2875.044, 'text': 'Well, what are those questions highlighted now in yellow, or what we would call Boolean, expressions named after a mathematician last name, bull,', 'start': 2867.461, 'duration': 7.583}, {'end': 2877.585, 'text': 'that simply have yes, no answers?', 'start': 2875.044, 'duration': 2.541}, {'end': 2886.511, 'text': 'Or if you prefer true or false answers or heck if you prefer one or zero answers, we just need to distinguish one scenario from another.', 'start': 2877.825, 'duration': 8.686}], 'summary': 'Functions solve small problems, conditionals are based on yes/no answers.', 'duration': 54.061, 'max_score': 2832.45, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2832450.jpg'}], 'start': 2421.939, 'title': 'Algorithm efficiency and problem solving', 'summary': 'Discusses the impact of algorithmic efficiency on problem solving, highlighting benefits of efficient algorithms in terms of time, steps, and emphasizes problem-solving techniques and program understanding in programming.', 'chapters': [{'end': 2670.875, 'start': 2421.939, 'title': 'Algorithm efficiency and performance', 'summary': 'Discusses the efficiency and performance of different algorithms using a graphical representation, highlighting the impact of algorithmic efficiency on solving problems with increasing size and the benefits of using a more efficient algorithm in terms of time and steps taken.', 'duration': 248.936, 'highlights': ['The third algorithm, with a logarithmic relationship between the size of the problem and the time required to solve it, demonstrates a significantly different and more efficient approach compared to the first two algorithms, as it allows for the problem to be halved with each step, resulting in a minimal increase in time and steps even with a much larger phone book.', 'The second algorithm, while flawed, shows a different slope in its graphical representation, indicating a two to one or one to two relationship between the number of pages and the time taken to solve the problem, offering a more efficient approach compared to the first algorithm.', 'The first algorithm demonstrates a linear relationship between the number of pages in the phone book and the time taken to solve the problem, resulting in a straight line graphical representation and a one to one relationship between the number of pages and the number of seconds or page turns.']}, {'end': 2886.511, 'start': 2670.875, 'title': 'Problem solving and program understanding', 'summary': 'Discusses problem-solving techniques, including decision-making steps and handling corner cases in programming, emphasizing the importance of considering all possible scenarios and learning about functions, conditionals, and boolean expressions in programming.', 'duration': 215.636, 'highlights': ['The chapter emphasizes the importance of considering all possible scenarios and handling corner cases in programming to avoid bugs and mistakes, ultimately leading to better code.', 'The chapter introduces the concept of functions in programming, which are actions or verbs that solve smaller problems, emphasizing their role in solving bigger problems by performing specific tasks.', 'The chapter discusses conditionals in programming as decision-making forks in the road, enabling the execution of different actions based on the answer to specific questions.', 'The chapter introduces Boolean expressions in programming, which provide yes/no, true/false, or 1/0 answers to distinguish one scenario from another, highlighting their role in programming.']}], 'duration': 464.572, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2421939.jpg', 'highlights': ['The third algorithm demonstrates a logarithmic relationship, resulting in minimal increase in time and steps even with a larger phone book.', 'The second algorithm shows a more efficient approach with a two to one or one to two relationship between pages and time.', 'The first algorithm has a linear relationship between pages and time, resulting in a one to one relationship.', 'The chapter emphasizes considering all possible scenarios and handling corner cases in programming.', 'The chapter introduces the concept of functions in programming, emphasizing their role in solving bigger problems.', 'The chapter discusses conditionals in programming as decision-making forks in the road.', 'The chapter introduces Boolean expressions in programming, highlighting their role in programming.']}, {'end': 3715.093, 'segs': [{'end': 2926.308, 'src': 'embed', 'start': 2887.111, 'weight': 0, 'content': [{'end': 2892.054, 'text': 'The last thing manifest in this pseudo code is what I might highlight now and call loops.', 'start': 2887.111, 'duration': 4.943}, {'end': 2896.898, 'text': 'Some kind of cycle, some kind of directive that tells us to do something again and again.', 'start': 2892.635, 'duration': 4.263}, {'end': 2902.801, 'text': "so that I don't need a thousand line program to search a thousand page phone book.", 'start': 2897.598, 'duration': 5.203}, {'end': 2911.325, 'text': 'I can get away with a 13 line program but sort of repeat myself inherently in order to solve some problem until I get to that last step.', 'start': 2902.881, 'duration': 8.444}, {'end': 2913.966, 'text': 'So this then is what we might call pseudo code.', 'start': 2911.965, 'duration': 2.001}, {'end': 2923.451, 'text': 'And indeed there are other characteristics of programs that will touch on before long things like arguments and return values, variables and more.', 'start': 2914.466, 'duration': 8.985}, {'end': 2926.308, 'text': 'But unfortunately in most languages,', 'start': 2924.306, 'duration': 2.002}], 'summary': 'Pseudo code employs loops to solve problems efficiently, reducing a 1000-line program to 13 lines for searching a 1000-page phone book.', 'duration': 39.197, 'max_score': 2887.111, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2887111.jpg'}, {'end': 2992, 'src': 'embed', 'start': 2963.216, 'weight': 2, 'content': [{'end': 2968.36, 'text': "I mean there's more overhead and more syntax and clutter than there is an actual idea.", 'start': 2963.216, 'duration': 5.144}, {'end': 2973.663, 'text': "Now. that's not to say that you won't be able to understand this before long, because, honestly,", 'start': 2968.78, 'duration': 4.883}, {'end': 2980.306, 'text': "there's not that many patterns and programming languages have typically a much smaller vocabulary than any actual human language.", 'start': 2973.663, 'duration': 6.643}, {'end': 2986.969, 'text': 'But at first it might indeed look quite cryptic but you can perhaps infer I have no idea what these other lines do yet.', 'start': 2980.346, 'duration': 6.623}, {'end': 2992, 'text': 'But hello world is presumably quote unquote what will be printed on the screen.', 'start': 2987.089, 'duration': 4.911}], 'summary': 'Programming languages may seem cryptic at first, but have smaller vocabulary than human languages.', 'duration': 28.784, 'max_score': 2963.216, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2963216.jpg'}, {'end': 3088.701, 'src': 'embed', 'start': 3058.965, 'weight': 1, 'content': [{'end': 3060.886, 'text': 'and in javascript and other languages too.', 'start': 3058.965, 'duration': 1.921}, {'end': 3064.928, 'text': "But in a way where we don't have to worry about the distractions of syntax.", 'start': 3061.286, 'duration': 3.642}, {'end': 3067.709, 'text': 'So the world of scratch looks like this.', 'start': 3065.428, 'duration': 2.281}, {'end': 3072.952, 'text': "It's a web based or downloadable programming environment that has this layout here by default.", 'start': 3067.97, 'duration': 4.982}, {'end': 3080.116, 'text': 'on the left here will soon see is a palette of puzzle pieces, programming blocks that represent all of those ideas we just discussed.', 'start': 3072.952, 'duration': 7.164}, {'end': 3088.701, 'text': 'And by dragging and dropping these puzzle pieces or blocks over this to big area and connecting them together if it makes logical sense to do so,', 'start': 3080.236, 'duration': 8.465}], 'summary': 'Scratch is a web-based programming environment with puzzle pieces representing programming blocks.', 'duration': 29.736, 'max_score': 3058.965, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3058965.jpg'}, {'end': 3207.095, 'src': 'embed', 'start': 3177.189, 'weight': 3, 'content': [{'end': 3183.295, 'text': 'and whereas scratch, as a graphical language, categorizes things by the type of things that these pieces do.', 'start': 3177.189, 'duration': 6.106}, {'end': 3189.842, 'text': "We'll see that throughout this whole palette will have functions and variables and conditionals and bullying expressions and more,", 'start': 3183.355, 'duration': 6.487}, {'end': 3191.163, 'text': 'each in a different color and shape.', 'start': 3189.842, 'duration': 1.321}, {'end': 3199.952, 'text': 'So for instance, moving 10 steps or turning one way or the other would be functions categorized here is things like motion under looks in purple.', 'start': 3191.243, 'duration': 8.709}, {'end': 3207.095, 'text': 'You might have speech bubbles that you can create by dragging and dropping these that might say hello or whatever for some number of seconds,', 'start': 3200.212, 'duration': 6.883}], 'summary': 'Scratch uses graphical language with functions, variables, conditionals, and expressions in different colors and shapes.', 'duration': 29.906, 'max_score': 3177.189, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3177189.jpg'}, {'end': 3569.294, 'src': 'embed', 'start': 3539.701, 'weight': 4, 'content': [{'end': 3541.623, 'text': "Ask what's your name? But that's in white.", 'start': 3539.701, 'duration': 1.922}, {'end': 3546.828, 'text': "So we can change the question to anything we want and it's going to wait for the human to type in their answer.", 'start': 3541.643, 'duration': 5.185}, {'end': 3554.831, 'text': 'And this function called ask is a little different from the say block which just had this side effect of printing a speech bubble to the screen.', 'start': 3547.429, 'duration': 7.402}, {'end': 3560.712, 'text': 'The ask function is even more powerful in that, after it asks the human to type something in,', 'start': 3555.291, 'duration': 5.421}, {'end': 3569.294, 'text': "this function is going to hand you back what they typed in in the form of what's called a return value, which is stored ultimately in by default,", 'start': 3560.712, 'duration': 8.582}], 'summary': "The 'ask' function prompts user input and returns the typed answer.", 'duration': 29.593, 'max_score': 3539.701, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3539701.jpg'}], 'start': 2887.111, 'title': 'Introduction to pseudo code and scratch', 'summary': 'Introduces pseudo code and its use of loops, compares it with scratch, emphasizes simplicity, and potential for learning programming concepts. it also introduces the basics of programming in scratch, illustrating the use of functions, inputs, and outputs, and demonstrating the creation of interactive programs with user input and output.', 'chapters': [{'end': 3445.862, 'start': 2887.111, 'title': 'Introduction to pseudo code and scratch', 'summary': 'Introduces pseudo code as a concise way of representing complex programs, highlighting the use of loops to solve problems and the comparison of pseudo code with actual programming languages like scratch, emphasizing its simplicity and potential for learning programming concepts before diving into actual languages.', 'duration': 558.751, 'highlights': ['Pseudo code is a concise way to represent programs, allowing the use of loops to solve problems efficiently, as demonstrated by reducing a thousand-line program to just 13 lines for a phone book search.', 'Comparison of pseudo code with programming languages like Scratch emphasizes the clutter and overhead of syntax in actual languages, highlighting the potential difficulty for beginners in understanding the syntax.', 'Introduction of Scratch as a graphical programming language provides a simpler, distraction-free environment for learning programming fundamentals, enabling the use of puzzle pieces to illustrate logical programming concepts.']}, {'end': 3715.093, 'start': 3445.862, 'title': 'Introduction to scratch programming', 'summary': 'Introduces the basics of programming in scratch, illustrating the use of functions, inputs, and outputs, and demonstrating the creation of interactive programs with user input and output.', 'duration': 269.231, 'highlights': ['The program demonstrates the use of functions, inputs, and outputs in Scratch, making it user-friendly compared to typing out cryptic text.', 'The ask function in Scratch allows for user input and returns a value, providing interactive capabilities in the program.', 'The demonstration highlights the presence of multiple solutions in programming, emphasizing the importance of critical thinking and problem-solving skills in programming.']}], 'duration': 827.982, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU2887111.jpg', 'highlights': ['Pseudo code simplifies programs, reducing a thousand-line program to just 13 lines for a phone book search.', 'Scratch provides a distraction-free environment for learning programming fundamentals using puzzle pieces.', 'Comparison of pseudo code with Scratch emphasizes the clutter and overhead of syntax in actual languages, potentially difficult for beginners.', 'Demonstration in Scratch highlights the use of functions, inputs, and outputs, making it user-friendly.', "Scratch's ask function allows for user input and returns a value, providing interactive capabilities in the program.", 'Demonstration emphasizes the presence of multiple solutions in programming, highlighting critical thinking and problem-solving skills.']}, {'end': 4688.923, 'segs': [{'end': 3742.572, 'src': 'embed', 'start': 3715.133, 'weight': 1, 'content': [{'end': 3719.297, 'text': 'But the more programs you write, the more feedback you get, the more bugs that you introduce,', 'start': 3715.133, 'duration': 4.164}, {'end': 3723.42, 'text': "the more you'll get your footing with exactly this kind of problem solving.", 'start': 3719.837, 'duration': 3.583}, {'end': 3725.541, 'text': 'So let me try this in a couple of ways.', 'start': 3723.46, 'duration': 2.081}, {'end': 3728.163, 'text': 'Up here would be one solution to the problem.', 'start': 3725.961, 'duration': 2.202}, {'end': 3732.866, 'text': 'MIT anticipated this kind of issue, especially with first time programmers.', 'start': 3728.303, 'duration': 4.563}, {'end': 3740.011, 'text': 'And I could just use puzzle piece that says say the following for two seconds or one second or whatever, then do the same with the next word.', 'start': 3733.206, 'duration': 6.805}, {'end': 3742.572, 'text': 'And it might be kind of a bit of a pause.', 'start': 3740.071, 'duration': 2.501}], 'summary': 'Writing more programs and receiving feedback helps improve problem-solving skills in programming.', 'duration': 27.439, 'max_score': 3715.133, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3715133.jpg'}, {'end': 3844.268, 'src': 'embed', 'start': 3819.865, 'weight': 3, 'content': [{'end': 3827.85, 'text': "Ask something and wait and notice that in this case too, there's an input, otherwise known henceforth as an argument or a parameter.", 'start': 3819.865, 'duration': 7.985}, {'end': 3830.852, 'text': 'programming speak for just an input in the context of a function.', 'start': 3827.85, 'duration': 3.002}, {'end': 3837.78, 'text': "And if we use our drawing as before to represent this thing here, we'll see that the input now is going to be quote unquote.", 'start': 3831.252, 'duration': 6.528}, {'end': 3838.421, 'text': "What's your name?", 'start': 3837.8, 'duration': 0.621}, {'end': 3844.268, 'text': 'The algorithm is going to be implemented by way of this new puzzle piece, the function called ask,', 'start': 3838.942, 'duration': 5.326}], 'summary': 'Introduction to programming concepts with a focus on function inputs.', 'duration': 24.403, 'max_score': 3819.865, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3819865.jpg'}, {'end': 3967.465, 'src': 'embed', 'start': 3942.873, 'weight': 4, 'content': [{'end': 3949.437, 'text': 'and you just have to learn to recognize the vocabulary and to know what kinds of puzzle pieces or concepts ultimately to apply.', 'start': 3942.873, 'duration': 6.564}, {'end': 3952.178, 'text': 'But you can ultimately really kind of spice these things up.', 'start': 3949.897, 'duration': 2.281}, {'end': 3955.38, 'text': 'Let me go back to my program here that just is using the speech bubble at the moment.', 'start': 3952.218, 'duration': 3.162}, {'end': 3958.681, 'text': 'Scratches and aside has some pretty fancy interactive features too.', 'start': 3955.78, 'duration': 2.901}, {'end': 3965.685, 'text': 'I click the extensions button in the bottom left corner and let me go ahead and choose the text to speech extension.', 'start': 3958.781, 'duration': 6.904}, {'end': 3967.465, 'text': 'This is using a cloud service.', 'start': 3966.105, 'duration': 1.36}], 'summary': 'Learn to recognize vocabulary and apply concepts, spice up program with interactive features and text-to-speech extension.', 'duration': 24.592, 'max_score': 3942.873, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3942873.jpg'}, {'end': 4235.797, 'src': 'embed', 'start': 4191.31, 'weight': 5, 'content': [{'end': 4199.416, 'text': "And in code generally speaking, when you start to copy and paste puzzle pieces or text next week, you're probably not doing something quite well.", 'start': 4191.31, 'duration': 8.106}, {'end': 4206.161, 'text': 'So let me go ahead and throw away most of these to get rid of the duplication, keeping just two of the blocks that I care about.', 'start': 4199.496, 'duration': 6.665}, {'end': 4208.003, 'text': 'Let me grab the repeat block for now.', 'start': 4206.422, 'duration': 1.581}, {'end': 4210.845, 'text': 'Let me move this inside of the repeat block.', 'start': 4208.543, 'duration': 2.302}, {'end': 4211.926, 'text': "It's going to grow to fit it.", 'start': 4210.885, 'duration': 1.041}, {'end': 4223.145, 'text': 'Let me reconnect all this and change the 10 just to a three and now play So better.', 'start': 4212.306, 'duration': 10.839}, {'end': 4224.146, 'text': "It's the same thing.", 'start': 4223.225, 'duration': 0.921}, {'end': 4224.887, 'text': "It's still correct.", 'start': 4224.186, 'duration': 0.701}, {'end': 4231.653, 'text': "But now I've set the stage to let the cat meow, for instance, four times by changing one thing, 40 times by changing one thing,", 'start': 4224.907, 'duration': 6.746}, {'end': 4235.797, 'text': 'or I could just use the forever block and just walk away and it will meow forever instead.', 'start': 4231.653, 'duration': 4.144}], 'summary': 'Optimized code by reducing duplication, achieving same functionality with fewer blocks and changing parameters, enabling efficient execution.', 'duration': 44.487, 'max_score': 4191.31, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4191310.jpg'}, {'end': 4296.652, 'src': 'embed', 'start': 4257.537, 'weight': 0, 'content': [{'end': 4262.902, 'text': "But a principle of programming and really computer science is to leverage what we're going to now start calling abstraction.", 'start': 4257.537, 'duration': 5.365}, {'end': 4266.265, 'text': 'We have step by step instructions here.', 'start': 4263.382, 'duration': 2.883}, {'end': 4271.209, 'text': 'The repeat the play in the way that collectively implements this idea that we humans would call meowing.', 'start': 4266.305, 'duration': 4.904}, {'end': 4277.475, 'text': "Wouldn't it be nice to abstract away those several puzzle pieces into just one that literally just says what it does.", 'start': 4271.67, 'duration': 5.805}, {'end': 4280.779, 'text': "Meow Well here's where we can make our own blocks.", 'start': 4277.495, 'duration': 3.284}, {'end': 4285.223, 'text': 'Let me go over here to scratch under the pink block category here.', 'start': 4281.019, 'duration': 4.204}, {'end': 4287.806, 'text': 'And let me click make a block.', 'start': 4286.465, 'duration': 1.341}, {'end': 4291.769, 'text': 'And here I see a slightly different interface where I can choose a name for it.', 'start': 4288.506, 'duration': 3.263}, {'end': 4293.87, 'text': "I'm going to call it meow and I'm going to keep it simple.", 'start': 4291.789, 'duration': 2.081}, {'end': 4294.251, 'text': "That's it.", 'start': 4293.91, 'duration': 0.341}, {'end': 4295.712, 'text': 'No inputs to meow yet.', 'start': 4294.391, 'duration': 1.321}, {'end': 4296.652, 'text': "I'm just going to click.", 'start': 4296.032, 'duration': 0.62}], 'summary': "Programming principle: leverage abstraction, create custom block 'meow' without inputs.", 'duration': 39.115, 'max_score': 4257.537, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4257537.jpg'}, {'end': 4508.984, 'src': 'embed', 'start': 4481.552, 'weight': 10, 'content': [{'end': 4488.293, 'text': 'And as you program more and more, these are the kinds of instincts still start to acquire, so that one you can start to take a big assignment,', 'start': 4481.552, 'duration': 6.741}, {'end': 4489.953, 'text': 'a big problem, set something for homework.', 'start': 4488.293, 'duration': 1.66}, {'end': 4492.254, 'text': 'even that feels kind of overwhelming at first.', 'start': 4489.953, 'duration': 2.301}, {'end': 4493.934, 'text': 'Like oh my God, where do I even begin?', 'start': 4492.294, 'duration': 1.64}, {'end': 4499.856, 'text': 'But if you start to identify what are the sub problems of a bigger problem, then you can start making progress.', 'start': 4494.374, 'duration': 5.482}, {'end': 4500.956, 'text': 'And I do this to this day.', 'start': 4499.916, 'duration': 1.04}, {'end': 4508.984, 'text': "where, if I have to tackle some programming related project, I'm so easy to like drag my feet, or it's going to take forever to start,", 'start': 4501.596, 'duration': 7.388}], 'summary': 'Develop programming instincts to tackle big problems by breaking them into sub-problems, facilitating progress.', 'duration': 27.432, 'max_score': 4481.552, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4481552.jpg'}, {'end': 4698.047, 'src': 'embed', 'start': 4673.917, 'weight': 12, 'content': [{'end': 4680.64, 'text': "So I could indeed use this forever loop, because if I want my program to just constantly listen to me, well, let's literally do something forever,", 'start': 4673.917, 'duration': 6.723}, {'end': 4684.901, 'text': 'or at least forever as long as the program is running, until I explicitly hit stop.', 'start': 4680.64, 'duration': 4.261}, {'end': 4685.622, 'text': 'So let me grab that.', 'start': 4684.921, 'duration': 0.701}, {'end': 4687.162, 'text': 'Let me go to control.', 'start': 4685.922, 'duration': 1.24}, {'end': 4688.923, 'text': 'Let me grab the forever block.', 'start': 4687.602, 'duration': 1.321}, {'end': 4696.606, 'text': "Let me move the if inside of this forever block, reconnect this, go back up here, click the green flag and now nothing's happened yet.", 'start': 4689.263, 'duration': 7.343}, {'end': 4698.047, 'text': 'But let me try moving my cursor now.', 'start': 4696.646, 'duration': 1.401}], 'summary': 'Using forever loop to make program constantly listen until explicitly stopped.', 'duration': 24.13, 'max_score': 4673.917, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4673917.jpg'}], 'start': 3715.133, 'title': 'Programming concepts and practice', 'summary': 'Covers programming feedback, problem solving, and enhancing scratch programs, emphasizing the importance of practice and introducing the concept of functions. it also explores abstraction in programming and modularizing a program, showcasing the importance of breaking down assignments and using instincts to efficiently tackle programming-related projects.', 'chapters': [{'end': 3942.873, 'start': 3715.133, 'title': 'Programming feedback and problem solving', 'summary': 'Explores programming feedback and problem solving, emphasizing the importance of practice and introducing the concept of functions, demonstrating how they can be used to create sophisticated programs with simple mental models.', 'duration': 227.74, 'highlights': ['The concept of functions is introduced, demonstrating how they can be used to create sophisticated programs with simple mental models.', 'The importance of practice and feedback in programming is emphasized, highlighting how it helps in getting a better understanding of problem-solving.', 'The process of nesting functions and stacking inputs and outputs is explained, showcasing the elegance and flexibility of programming solutions.', 'The role of parameters and arguments in functions is illustrated, emphasizing the significance of inputs in the context of programming.']}, {'end': 4211.926, 'start': 3942.873, 'title': 'Enhancing scratch programs', 'summary': 'Explores enhancing scratch programs by incorporating interactive features, such as text-to-speech, sound effects, and loops, while emphasizing the importance of minimizing repetition and duplication in code.', 'duration': 269.053, 'highlights': ['The speaker demonstrates incorporating interactive features like text-to-speech and sound effects into Scratch programs, enhancing their functionality.', 'The chapter emphasizes the importance of minimizing repetition and duplication in code to avoid introducing potential bugs and increasing programming efficiency.', 'The speaker demonstrates the use of loops to minimize repetition and duplication in code, exemplifying the implementation of a repeat block to reduce unnecessary code duplication.']}, {'end': 4461.506, 'start': 4212.306, 'title': 'Abstraction in programming', 'summary': "Demonstrates the concept of abstraction in programming, where the speaker illustrates creating custom blocks 'meow' and 'meow with input' to simplify and improve code readability and maintainability, promoting the idea of leveraging abstraction in computer science.", 'duration': 249.2, 'highlights': ['The speaker demonstrates changing one thing in the code to set the stage for the cat to meow four times, emphasizing the impact of a small change on behavior.', "Illustrating the creation of the 'meow' custom block in Scratch, the speaker emphasizes the value of abstracting away multiple puzzle pieces into a single function, promoting code readability and maintainability.", "The concept of abstraction is further extended as the speaker creates a parameterized version of the 'meow' block, allowing it to take inputs that affect its behavior, enhancing the block's flexibility and reusability."]}, {'end': 4688.923, 'start': 4461.846, 'title': 'Programming design and problem solving', 'summary': 'Discusses the process of modularizing a program, creating sub-problems, and implementing solutions, showcasing the importance of breaking down assignments and using instincts to efficiently tackle programming-related projects.', 'duration': 227.077, 'highlights': ['The chapter emphasizes the importance of modularizing a program and creating sub-problems to efficiently tackle assignments.', 'The speaker discusses the instinctual process of efficiently tackling programming-related projects by breaking assignments into sub-problems.', 'The importance of using a forever loop to constantly listen to input and make the program continuously functional is highlighted.']}], 'duration': 973.79, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU3715133.jpg', 'highlights': ['The concept of functions is introduced, demonstrating how they can be used to create sophisticated programs with simple mental models.', 'The importance of practice and feedback in programming is emphasized, highlighting how it helps in getting a better understanding of problem-solving.', 'The process of nesting functions and stacking inputs and outputs is explained, showcasing the elegance and flexibility of programming solutions.', 'The role of parameters and arguments in functions is illustrated, emphasizing the significance of inputs in the context of programming.', 'The speaker demonstrates incorporating interactive features like text-to-speech and sound effects into Scratch programs, enhancing their functionality.', 'The chapter emphasizes the importance of minimizing repetition and duplication in code to avoid introducing potential bugs and increasing programming efficiency.', 'The speaker demonstrates the use of loops to minimize repetition and duplication in code, exemplifying the implementation of a repeat block to reduce unnecessary code duplication.', 'The speaker demonstrates changing one thing in the code to set the stage for the cat to meow four times, emphasizing the impact of a small change on behavior.', "Illustrating the creation of the 'meow' custom block in Scratch, the speaker emphasizes the value of abstracting away multiple puzzle pieces into a single function, promoting code readability and maintainability.", "The concept of abstraction is further extended as the speaker creates a parameterized version of the 'meow' block, allowing it to take inputs that affect its behavior, enhancing the block's flexibility and reusability.", 'The chapter emphasizes the importance of modularizing a program and creating sub-problems to efficiently tackle assignments.', 'The speaker discusses the instinctual process of efficiently tackling programming-related projects by breaking assignments into sub-problems.', 'The importance of using a forever loop to constantly listen to input and make the program continuously functional is highlighted.']}, {'end': 6280.053, 'segs': [{'end': 4952.271, 'src': 'embed', 'start': 4924.543, 'weight': 0, 'content': [{'end': 4930.184, 'text': 'but assembling them in a fun way with some music, maybe some new costumes or artwork, you can really bring programs to life.', 'start': 4924.543, 'duration': 5.641}, {'end': 4936.285, 'text': 'But at the end of the day, the only puzzle pieces really involved were ones like the ones I just dragged and dropped and a few more,', 'start': 4930.404, 'duration': 5.881}, {'end': 4937.686, 'text': 'because there were clearly lots of moles.', 'start': 4936.285, 'duration': 1.401}, {'end': 4943.187, 'text': 'So the student probably created a few different sprites, not a single cap, but at least four different moles.', 'start': 4938.046, 'duration': 5.141}, {'end': 4947.069, 'text': 'They had like some kind of graphic on the screen that showed so hard where to position her head.', 'start': 4943.447, 'duration': 3.622}, {'end': 4952.271, 'text': 'There was some kind of timer, maybe a variable that every second was counting down.', 'start': 4947.349, 'duration': 4.922}], 'summary': 'Using fun elements like music and costumes, the student created at least four different moles and implemented a timer in their program.', 'duration': 27.728, 'max_score': 4924.543, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4924543.jpg'}, {'end': 4977.266, 'src': 'embed', 'start': 4952.311, 'weight': 1, 'content': [{'end': 4957.993, 'text': 'So you can imagine taking what looks like a pretty impressive project at first glance and perhaps overwhelming to solve yourself.', 'start': 4952.311, 'duration': 5.682}, {'end': 4964.596, 'text': 'But just think about what are the basic building blocks and pluck off one piece of the puzzle so to speak at a time.', 'start': 4958.393, 'duration': 6.203}, {'end': 4973.202, 'text': 'And so indeed, if we rewind a little bit, Let me go ahead here and introduce a program that I myself made back in graduate school,', 'start': 4964.916, 'duration': 8.286}, {'end': 4975.404, 'text': 'when scratch was first being developed by MIT.', 'start': 4973.202, 'duration': 2.202}, {'end': 4977.266, 'text': 'Let me go ahead and open here.', 'start': 4975.764, 'duration': 1.502}], 'summary': 'Discussing breaking down complex projects into manageable pieces.', 'duration': 24.955, 'max_score': 4952.311, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4952311.jpg'}, {'end': 5184.118, 'src': 'heatmap', 'start': 5113.812, 'weight': 1, 'content': [{'end': 5116.694, 'text': 'But it got me to version one of my program.', 'start': 5113.812, 'duration': 2.882}, {'end': 5118.535, 'text': 'Then what might version to be?', 'start': 5116.994, 'duration': 1.541}, {'end': 5124.78, 'text': 'Well, I considered what piece of functionality, frankly, might be the easiest to pluck off next and the trash can.', 'start': 5118.795, 'duration': 5.985}, {'end': 5126.722, 'text': 'that seems like a pretty core piece of functionality.', 'start': 5124.78, 'duration': 1.942}, {'end': 5128.885, 'text': 'It just needs to sit there most of the time.', 'start': 5127.062, 'duration': 1.823}, {'end': 5138.776, 'text': 'So the next thing I probably did was to open up for instance the trash can version here that looks a little something now like this.', 'start': 5129.245, 'duration': 9.531}, {'end': 5140.638, 'text': "So this time I'll show you what's inside here.", 'start': 5139.076, 'duration': 1.562}, {'end': 5144.262, 'text': 'There is some code but not much notice at bottom right.', 'start': 5140.678, 'duration': 3.584}, {'end': 5147.486, 'text': 'I changed the default cat to a picture of a trash can instead.', 'start': 5144.362, 'duration': 3.124}, {'end': 5149.869, 'text': "But it's the same principle that I can control.", 'start': 5147.546, 'duration': 2.323}, {'end': 5154.254, 'text': 'And then over here I added this code when the green flag is clicked.', 'start': 5150.27, 'duration': 3.984}, {'end': 5157.657, 'text': 'switch the costume to something I arbitrarily called Oscar one.', 'start': 5154.835, 'duration': 2.822}, {'end': 5161.52, 'text': 'So I found a couple of different pictures of a trash can one that looks closed,', 'start': 5157.717, 'duration': 3.803}, {'end': 5166.104, 'text': 'one that looks partly open and eventually one that has Oscar coming out, and I just gave them different names.', 'start': 5161.52, 'duration': 4.584}, {'end': 5169.826, 'text': 'So I said switch to Oscar one, which is the closed one by default.', 'start': 5166.504, 'duration': 3.322}, {'end': 5178.033, 'text': 'then forever do the following if touching the mouse pointer, then switch the costume to Oscar, to else switch to Oscar one.', 'start': 5169.826, 'duration': 8.207}, {'end': 5184.118, 'text': "That is to say I just wanted to implement this idea of like the can opening and closing even if it's not exactly what I wanted.", 'start': 5178.553, 'duration': 5.565}], 'summary': 'Program version one includes trash can functionality with code and images.', 'duration': 70.306, 'max_score': 5113.812, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU5113812.jpg'}, {'end': 5230.066, 'src': 'embed', 'start': 5208.075, 'weight': 4, 'content': [{'end': 5217.959, 'text': "And if I went in now and added the lamppost and compose the program together now we're starting to make progress right now it would look a little something more like the program I intended ultimately to create.", 'start': 5208.075, 'duration': 9.884}, {'end': 5220.461, 'text': 'what piece did I probably bite off after that??', 'start': 5217.959, 'duration': 2.502}, {'end': 5226.844, 'text': 'Well, I think what I did is I probably decided let me implement one of the pieces of trash, not the shoe and the newspaper all at once.', 'start': 5220.541, 'duration': 6.303}, {'end': 5230.066, 'text': "Let's just get one piece of trash working correctly first.", 'start': 5226.904, 'duration': 3.162}], 'summary': 'Incremental progress is being made in programming by adding one piece at a time.', 'duration': 21.991, 'max_score': 5208.075, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU5208075.jpg'}, {'end': 5642.148, 'src': 'embed', 'start': 5599.634, 'weight': 2, 'content': [{'end': 5606.919, 'text': 'Reuse the code that you wrote, reuse the sprites that you wrote and that would give you not just correctness but also a better design.', 'start': 5599.634, 'duration': 7.285}, {'end': 5614.551, 'text': "Well, let's take a look at one final set of building blocks that we can compose ultimately into something particularly interactive as follows.", 'start': 5607.44, 'duration': 7.111}, {'end': 5620.861, 'text': 'Let me go ahead and zoom out here and let me propose that we implement something like like some kind of maze based game.', 'start': 5614.591, 'duration': 6.27}, {'end': 5622.261, 'text': 'And let me go ahead here.', 'start': 5621.141, 'duration': 1.12}, {'end': 5627.583, 'text': 'So I want to implement some maze based game that looks at first glance like this.', 'start': 5622.762, 'duration': 4.821}, {'end': 5628.324, 'text': 'Let me hit play.', 'start': 5627.623, 'duration': 0.701}, {'end': 5629.904, 'text': "It's not a very fun game yet.", 'start': 5628.784, 'duration': 1.12}, {'end': 5634.606, 'text': "But here's a little harvard shield a couple of black lines this time vertical instead of horizontal.", 'start': 5629.944, 'duration': 4.662}, {'end': 5642.148, 'text': "But notice you can't quite see my hand here but I'm using my arrow keys to go down to go up to go left to go right.", 'start': 5635.026, 'duration': 7.122}], 'summary': 'Code and sprites can improve design. proposal for maze-based game with arrow key controls.', 'duration': 42.514, 'max_score': 5599.634, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU5599634.jpg'}], 'start': 4689.263, 'title': 'Interactive coding and game development', 'summary': 'Explores creating interactivity in coding through custom blocks, simple building blocks, scratch programming, and maze-based game implementation, emphasizing the use of basic components and programming abstractions in developing interactive programs and games.', 'chapters': [{'end': 4725.127, 'start': 4689.263, 'title': 'Interactive coding with custom blocks', 'summary': 'Explores creating interactivity in coding by assembling different puzzle pieces and using custom blocks, resulting in more complex and responsive programs.', 'duration': 35.864, 'highlights': ['The chapter emphasizes the idea of assembling different puzzle pieces into something more complicated.', 'It highlights the concept of creating custom blocks to enhance interactivity in coding.', "Demonstrates the use of 'when green flag clicked' for initiating interactivity in the program."]}, {'end': 5030.47, 'start': 4725.728, 'title': 'Interactive programming and simple building blocks', 'summary': 'Highlights the interactive nature of programming, showcasing projects that use basic building blocks to create interactive programs, such as a virtual whack-a-mole game and an interactive trash disposal program, emphasizing the use of simple components to bring programs to life.', 'duration': 304.742, 'highlights': ['The chapter demonstrates the creation of interactive programs using basic building blocks and simple components.', 'The chapter emphasizes the interactive nature of programming through a demonstration of an interactive trash disposal program.', 'The chapter illustrates the interactive aspect of programming by involving a volunteer in an interactive virtual whack-a-mole game.']}, {'end': 5469.232, 'start': 5030.931, 'title': 'Creating a program with scratch', 'summary': 'Discusses the process of creating a program with scratch, starting with implementing individual components such as a lamp post, trash can, and pieces of trash, and then combining them to make a functional program, with details on the code and logic behind each step.', 'duration': 438.301, 'highlights': ['The process of creating a program with Scratch, starting with implementing individual components such as a lamp post, trash can, and pieces of trash, and then combining them to make a functional program', 'Implementing a lamp post as the first step, using drag and drop features to create version one of the program', 'Adding functionality to the trash can by coding it to switch costumes and open and close when the mouse pointer is nearby', 'Implementing the falling of trash and using logic to stop its movement upon touching the floor, demonstrating the use of randomness and logical conditions', 'Implementing the dragging of trash through code logic, allowing the user to move the trash up, down, left, and right']}, {'end': 5734.477, 'start': 5469.592, 'title': 'Implementing maze-based game with code', 'summary': 'Discusses implementing a maze-based game using reusable code, with the use of variables and conditional statements, to create an interactive game with movement and collision detection.', 'duration': 264.885, 'highlights': ['Implementing reusable code and sprites for a better design', 'Creating a maze-based game with movement and collision detection', 'Use of variables and conditional statements for score keeping']}, {'end': 6280.053, 'start': 5734.477, 'title': 'Programming abstractions and game development', 'summary': 'Introduces programming abstractions and game development, demonstrating the implementation of custom blocks and advanced adversaries in game programming, with examples of bouncing adversaries and a sprite following the player.', 'duration': 545.576, 'highlights': ['The program implements abstractions and custom blocks to explain the code, simplifying overwhelming concepts for aspiring programmers.', 'The implementation of listening for keyboard inputs and wall collisions is demonstrated, showcasing the use of custom blocks to hide implementation details.', 'The development of adversaries in game programming is explored, with examples of bouncing adversaries and a sprite following the player, demonstrating programming logic and implementation.']}], 'duration': 1590.79, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/1tnj3UCkuxU/pics/1tnj3UCkuxU4689263.jpg', 'highlights': ['The chapter emphasizes the idea of assembling different puzzle pieces into something more complicated.', 'The program implements abstractions and custom blocks to explain the code, simplifying overwhelming concepts for aspiring programmers.', 'The chapter demonstrates the creation of interactive programs using basic building blocks and simple components.', 'Creating a maze-based game with movement and collision detection', 'The process of creating a program with Scratch, starting with implementing individual components such as a lamp post, trash can, and pieces of trash, and then combining them to make a functional program']}], 'highlights': ['Computer science fosters methodical and precise thinking, with two-thirds of CS50 students never having taken a CS course before.', 'The ability to create something and bring a computer to life to solve a problem is challenging, frustrating, and gratifying (e.g. dealing with bugs and taking breaks).', 'Understanding programming becomes easier with time, enabling individuals to learn other languages as well.', 'The divide and conquer algorithm reduces search space by half for more efficient search.', 'The miniaturization of hardware allows for increased data storage.', 'Pseudo code simplifies programs, reducing a thousand-line program to just 13 lines for a phone book search.', 'The process of nesting functions and stacking inputs and outputs is explained, showcasing the elegance and flexibility of programming solutions.', 'The chapter emphasizes the idea of assembling different puzzle pieces into something more complicated.', 'Creating a maze-based game with movement and collision detection', 'The chapter demonstrates the creation of interactive programs using basic building blocks and simple components.']}