title
3.8 Infix to Prefix using Stack | Data Structures Tutorials

description
In this lecture, I have described an efficient algorithm for infix to prefix conversion using stack in data structure. Also discussed infix to prefix conversion without stack with example and analyzed both the approaches. DSA Full Course: https: https://www.youtube.com/playlist?list=PLdo5W4Nhv31bbKJzrsKfMpo_grxuLl8LU ****************************************** See Complete Playlists: C Programming Course: https://www.youtube.com/playlist?list=PLdo5W4Nhv31a8UcMN9-35ghv8qyFWD9_S C++ Programming: https://www.youtube.com/playlist?list=PLdo5W4Nhv31YU5Wx1dopka58teWP9aCee Python Full Course: https://www.youtube.com/playlist?list=PLdo5W4Nhv31bZSiqiOL5ta39vSnBxpOPT Printing Pattern in C: https://www.youtube.com/playlist?list=PLdo5W4Nhv31Yu1igxTE2x0aeShbKtVcCy DAA Course: https://www.youtube.com/playlist?list=PLdo5W4Nhv31ZTn2P9vF02bkb3SC8uiUUn Placement Series: https://www.youtube.com/playlist?list=PLdo5W4Nhv31YvlDpJhvOYbM9Ap8UypgEy Dynamic Programming: https://www.youtube.com/playlist?list=PLdo5W4Nhv31aBrJE1WS4MR9LRfbmZrAQu Operating Systems: //www.youtube.com/playlist?list=PLdo5W4Nhv31a5ucW_S1K3-x6ztBRD-PNa DBMS: https://www.youtube.com/playlist?list=PLdo5W4Nhv31b33kF46f9aFjoJPOkdlsRc ********************************************* Connect & Contact Me: Facebook: https://www.facebook.com/Jennys-Lectures-CSIT-Netjrf-316814368950701/ Quora: https://www.quora.com/profile/Jayanti-Khatri-Lamba Instagram: https://www.instagram.com/jayantikhatrilamba/ #stack #infixtopostfix #jennyslectures

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{'title': '3.8 Infix to Prefix using Stack | Data Structures Tutorials', 'heatmap': [{'end': 436.135, 'start': 402.414, 'weight': 1}], 'summary': 'Covers various topics including infix to prefix conversion with stack, infix to prefix conversion, infix to postfix conversion, prefix, operator precedence, and conversion using stack, and converting infix expressions to prefix notation, highlighting the efficiency and rules for each conversion method.', 'chapters': [{'end': 177.956, 'segs': [{'end': 25.818, 'src': 'embed', 'start': 0.606, 'weight': 0, 'content': [{'end': 7.009, 'text': 'so in this lecture we are going to see how to convert infix expression into prefix expression.', 'start': 0.606, 'duration': 6.403}, {'end': 12.752, 'text': 'in the previous video i have discussed the infix to postfix conversion using stack.', 'start': 7.009, 'duration': 5.743}, {'end': 17.414, 'text': 'now we will see the infix to prefix conversion using stack right.', 'start': 12.752, 'duration': 4.662}, {'end': 24.497, 'text': 'see, here, also without stack, you can convert from infix to prefix, like we have discussed in the previous case.', 'start': 17.414, 'duration': 7.083}, {'end': 25.818, 'text': 'see, let us take this example.', 'start': 24.497, 'duration': 1.321}], 'summary': 'Lecture on converting infix to prefix expression using stack.', 'duration': 25.212, 'max_score': 0.606, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI606.jpg'}, {'end': 177.956, 'src': 'embed', 'start': 123.188, 'weight': 1, 'content': [{'end': 132.27, 'text': 'Now for prefix this operator should be before these operands a and second operand is this one means asterisk b c.', 'start': 123.188, 'duration': 9.082}, {'end': 137.914, 'text': 'right. so this is what you can say a prefix for the syntax, right in this case.', 'start': 132.99, 'duration': 4.924}, {'end': 143.138, 'text': 'also in first scan, this will be solved in second scan.', 'start': 137.914, 'duration': 5.224}, {'end': 146.321, 'text': 'again we will solve for this plus right.', 'start': 143.138, 'duration': 3.183}, {'end': 151.385, 'text': 'so there are multiple scans to solve this problem without using stack.', 'start': 146.321, 'duration': 5.064}, {'end': 153.687, 'text': 'now here in this case I am solving this.', 'start': 151.385, 'duration': 2.302}, {'end': 155.048, 'text': 'this is a smaller expression.', 'start': 153.687, 'duration': 1.361}, {'end': 163.985, 'text': 'if this is the expression, then here multiple scans would be there, maybe 10 or maybe 15, I cannot say right Now,', 'start': 155.048, 'duration': 8.937}, {'end': 170.71, 'text': 'rather than scanning it multiple times, because this process is, you know, very time consuming process, very lengthy process.', 'start': 163.985, 'duration': 6.725}, {'end': 177.956, 'text': 'So we should follow a method in which we scan only once from here to here.', 'start': 171.371, 'duration': 6.585}], 'summary': 'Multiple scans required to solve the problem without using stack, potentially 10-15 scans, but should follow a method to scan only once from start to end.', 'duration': 54.768, 'max_score': 123.188, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI123188.jpg'}], 'start': 0.606, 'title': 'Infix to prefix conversion with stack', 'summary': 'Discusses the conversion of infix expression to prefix expression using stack, emphasizing the precedence and associativity of operators. it also highlights the efficiency of the method in reducing the number of scans to solve the problem.', 'chapters': [{'end': 177.956, 'start': 0.606, 'title': 'Infix to prefix conversion with stack', 'summary': 'Discusses the conversion of infix expression to prefix expression using stack, emphasizing the precedence and associativity of operators and the efficiency of the method in reducing the number of scans to solve the problem.', 'duration': 177.35, 'highlights': ['The lecture covers the conversion of infix expression to prefix expression using stack, emphasizing the importance of knowing the precedence and associativity of operators.', 'Precedence and associativity rules are followed to solve the expression, with the higher precedence operator being addressed first, leading to the reduction of scans and increased efficiency.', 'The method aims to minimize the number of scans required to solve the problem, as scanning the expression multiple times is described as time-consuming and lengthy.']}], 'duration': 177.35, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI606.jpg', 'highlights': ['The lecture covers the conversion of infix expression to prefix expression using stack, emphasizing the importance of knowing the precedence and associativity of operators.', 'Precedence and associativity rules are followed to solve the expression, with the higher precedence operator being addressed first, leading to the reduction of scans and increased efficiency.', 'The method aims to minimize the number of scans required to solve the problem, as scanning the expression multiple times is described as time-consuming and lengthy.']}, {'end': 328.851, 'segs': [{'end': 208.097, 'src': 'embed', 'start': 178.817, 'weight': 3, 'content': [{'end': 183.18, 'text': 'and after reaching at the end of this expression we will get our output.', 'start': 178.817, 'duration': 4.363}, {'end': 185.562, 'text': 'you can say we will get a prefix expression.', 'start': 183.18, 'duration': 2.382}, {'end': 190.525, 'text': "we don't need to scan this expression multiple times, right?", 'start': 185.562, 'duration': 4.963}, {'end': 191.305, 'text': 'so that is.', 'start': 190.525, 'duration': 0.78}, {'end': 195.888, 'text': 'that would be what efficient algorithm so that is possible using stack.', 'start': 191.305, 'duration': 4.583}, {'end': 200.411, 'text': "that is why here i'll discuss with you conversion of infix to prefix using stack.", 'start': 195.888, 'duration': 4.523}, {'end': 203.193, 'text': 'we will also discuss, to tell you, our answer.', 'start': 200.411, 'duration': 2.782}, {'end': 208.097, 'text': 'we will also discuss how you can convert this expression without using step at last.', 'start': 203.193, 'duration': 4.904}], 'summary': 'Efficiently convert infix to prefix using stack, avoiding multiple scans.', 'duration': 29.28, 'max_score': 178.817, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI178817.jpg'}, {'end': 328.851, 'src': 'embed', 'start': 282.075, 'weight': 0, 'content': [{'end': 287.56, 'text': 'you can do something like this after that convert this into postfix and after that reverse that postfix expression.', 'start': 282.075, 'duration': 5.485}, {'end': 289.081, 'text': 'but i am not going to do this.', 'start': 287.56, 'duration': 1.521}, {'end': 291.003, 'text': 'i am going to follow the second approach.', 'start': 289.081, 'duration': 1.922}, {'end': 293.705, 'text': 'right, this is now a reverse infix expression.', 'start': 291.003, 'duration': 2.702}, {'end': 295.287, 'text': 'now, see, same.', 'start': 293.705, 'duration': 1.582}, {'end': 297.449, 'text': 'we are going to take one stack.', 'start': 295.287, 'duration': 2.162}, {'end': 304.675, 'text': 'if operator will be found, then we are using stack for pushing those operators and if operand is there,', 'start': 297.449, 'duration': 7.226}, {'end': 312.717, 'text': 'then directly we are going to print those operands right now.', 'start': 304.675, 'duration': 8.042}, {'end': 316.46, 'text': 'now, scan this reverse infix expression from left to right.', 'start': 312.717, 'duration': 3.743}, {'end': 321.444, 'text': 'you can scan it from right to left also, and after that also you can get the prefix expression.', 'start': 316.46, 'duration': 4.984}, {'end': 325.348, 'text': 'so there are many ways, two or three ways, to convert infix to prefix right.', 'start': 321.444, 'duration': 3.904}, {'end': 328.851, 'text': 'this is one of all the possible ways right now.', 'start': 325.348, 'duration': 3.503}], 'summary': 'Exploring methods to convert infix to prefix expressions using stacks and scanning techniques.', 'duration': 46.776, 'max_score': 282.075, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI282075.jpg'}], 'start': 178.817, 'title': 'Infix to prefix conversion', 'summary': 'Discusses the efficient algorithm of converting infix to prefix using a stack, presenting the process and rules, and highlighting the various approaches to achieve the conversion.', 'chapters': [{'end': 328.851, 'start': 178.817, 'title': 'Infix to prefix conversion using stack', 'summary': 'Discusses the efficient algorithm of converting infix to prefix using a stack, presenting the process and rules, and highlighting the various approaches to achieve the conversion.', 'duration': 150.034, 'highlights': ['The chapter discusses the efficient algorithm of converting infix to prefix using a stack, presenting the process and rules, and highlighting the various approaches to achieve the conversion.', 'The conversion of infix to prefix using a stack is similar to infix to postfix conversion, but it requires the infix expression to be reversed before further processing.', 'The process involves scanning the reverse infix expression from left to right, pushing operators onto a stack and printing operands to obtain the prefix expression.', 'There are multiple approaches to convert infix to prefix, including reversing the infix expression and then converting it to postfix before reversing the result, but the chapter focuses on an alternative approach.']}], 'duration': 150.034, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI178817.jpg', 'highlights': ['The process involves scanning the reverse infix expression from left to right, pushing operators onto a stack and printing operands to obtain the prefix expression.', 'The conversion of infix to prefix using a stack is similar to infix to postfix conversion, but it requires the infix expression to be reversed before further processing.', 'There are multiple approaches to convert infix to prefix, including reversing the infix expression and then converting it to postfix before reversing the result, but the chapter focuses on an alternative approach.', 'The chapter discusses the efficient algorithm of converting infix to prefix using a stack, presenting the process and rules, and highlighting the various approaches to achieve the conversion.']}, {'end': 628.795, 'segs': [{'end': 375.371, 'src': 'embed', 'start': 350.968, 'weight': 1, 'content': [{'end': 356.852, 'text': 'write down here, print it right now we have a strict operator or multiplication operator.', 'start': 350.968, 'duration': 5.884}, {'end': 359.334, 'text': 'you can say now, check.', 'start': 356.852, 'duration': 2.482}, {'end': 362.236, 'text': 'if in stack i have plus top of the stack, is this one.', 'start': 359.334, 'duration': 2.902}, {'end': 364.177, 'text': 'now we are going to check the precedence.', 'start': 362.236, 'duration': 1.941}, {'end': 365.718, 'text': 'see now the.', 'start': 364.177, 'duration': 1.541}, {'end': 375.371, 'text': 'if the incoming operator is having higher precedence, then the top of the stack, then what you will do, simply push this operator.', 'start': 365.718, 'duration': 9.653}], 'summary': 'Explanation of operator precedence and stack operations.', 'duration': 24.403, 'max_score': 350.968, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI350968.jpg'}, {'end': 453.204, 'src': 'heatmap', 'start': 402.414, 'weight': 0, 'content': [{'end': 405.837, 'text': 'associativity of this is what left to right.', 'start': 402.414, 'duration': 3.423}, {'end': 412.803, 'text': 'so if associativity is left to right, then simply push the incoming operator into the stack.', 'start': 405.837, 'duration': 6.966}, {'end': 418.289, 'text': 'right, but that is not a case in infix to post fix conversion.', 'start': 414.008, 'duration': 4.281}, {'end': 427.652, 'text': 'in that case, if associativity is left to right, then pop out this one right and again check the incoming operator with the new top of the stack.', 'start': 418.289, 'duration': 9.363}, {'end': 436.135, 'text': 'but here the rule is different, because we are converting infix to prefix now right so now, here we have q, t and v.', 'start': 427.652, 'duration': 8.483}, {'end': 438.216, 'text': 'now we have u means.', 'start': 436.135, 'duration': 2.081}, {'end': 442.579, 'text': 'simply write down here V, U.', 'start': 439.577, 'duration': 3.002}, {'end': 443.999, 'text': 'now again we have divide.', 'start': 442.579, 'duration': 1.42}, {'end': 447.661, 'text': 'check out the top of the stack is having divide same precedence operator is there?', 'start': 443.999, 'duration': 3.662}, {'end': 450.342, 'text': 'incoming operator is the same precedence of this operator?', 'start': 447.661, 'duration': 2.681}, {'end': 453.204, 'text': 'now? check out the associativity rule left to right.', 'start': 450.342, 'duration': 2.862}], 'summary': 'Explaining infix to prefix conversion with associativity rules.', 'duration': 47.367, 'max_score': 402.414, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI402414.jpg'}, {'end': 598.954, 'src': 'embed', 'start': 570.392, 'weight': 3, 'content': [{'end': 578.82, 'text': 'in this case, if you find any opening parenthesis, if the next symbol is opening parenthesis, then what you will do?', 'start': 570.392, 'duration': 8.428}, {'end': 580.242, 'text': 'then from the stack?', 'start': 578.82, 'duration': 1.422}, {'end': 590.412, 'text': 'pop out all the operators, one by one, right till you find the closing parenthesis corresponding to this opening parenthesis.', 'start': 580.242, 'duration': 10.17}, {'end': 592.254, 'text': 'right here the rule is reverse.', 'start': 590.412, 'duration': 1.842}, {'end': 597.032, 'text': 'Now, see, we have top of the stack is having exponent.', 'start': 593.109, 'duration': 3.923}, {'end': 598.954, 'text': 'So first of all pop out this one.', 'start': 597.052, 'duration': 1.902}], 'summary': 'Algorithm processes opening parenthesis and operators from stack in reverse order.', 'duration': 28.562, 'max_score': 570.392, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI570392.jpg'}], 'start': 328.851, 'title': 'Infix to postfix conversion', 'summary': 'Explains the process of converting infix expressions to postfix expressions, involving stack manipulation, precedence and associativity rules, and the rules for pushing and popping parentheses and operators into a stack.', 'chapters': [{'end': 480.697, 'start': 328.851, 'title': 'Infix to prefix conversion', 'summary': 'Explains the process of converting infix expressions to prefix expressions, involving the evaluation of operators, checking precedence and associativity rules, and stack manipulation.', 'duration': 151.846, 'highlights': ['The process involves evaluating operators, checking precedence and associativity rules, and manipulating the stack.', 'The chapter emphasizes the importance of checking the precedence and associativity of incoming operators compared to those in the stack.', 'The explanation highlights the specific rules and considerations for converting infix to prefix expressions, including the handling of associativity rules and stack manipulation.']}, {'end': 628.795, 'start': 480.757, 'title': 'Stack operations in infix to postfix conversion', 'summary': 'Discusses the rules for pushing and popping parentheses and operators into a stack during the process of converting infix to postfix notation, emphasizing the reverse rule for parentheses and the importance of stack operations in handling different symbols and operators.', 'duration': 148.038, 'highlights': ['The rule for pushing and popping parentheses into the stack is different based on whether it is an opening or closing parenthesis, with the reverse rule applied when it comes to handling closing parentheses, emphasizing the importance of understanding the specific rules for each type of parenthesis.', 'The process of pushing and popping operators into the stack is described, emphasizing the simplicity of pushing and the need to check precedence when pushing operators, highlighting the significance of the stack in managing operators during the conversion process.', 'The specific actions of pushing and popping parentheses and operators into the stack are detailed, providing a clear understanding of the step-by-step process and the importance of correctly handling different symbols and operators in the stack.']}], 'duration': 299.944, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI328851.jpg', 'highlights': ['The process involves evaluating operators, checking precedence and associativity rules, and manipulating the stack.', 'The chapter emphasizes the importance of checking the precedence and associativity of incoming operators compared to those in the stack.', 'The explanation highlights the specific rules and considerations for converting infix to prefix expressions, including the handling of associativity rules and stack manipulation.', 'The rule for pushing and popping parentheses into the stack is different based on whether it is an opening or closing parenthesis, with the reverse rule applied when it comes to handling closing parentheses, emphasizing the importance of understanding the specific rules for each type of parenthesis.', 'The process of pushing and popping operators into the stack is described, emphasizing the simplicity of pushing and the need to check precedence when pushing operators, highlighting the significance of the stack in managing operators during the conversion process.', 'The specific actions of pushing and popping parentheses and operators into the stack are detailed, providing a clear understanding of the step-by-step process and the importance of correctly handling different symbols and operators in the stack.']}, {'end': 875.561, 'segs': [{'end': 652.593, 'src': 'embed', 'start': 628.795, 'weight': 0, 'content': [{'end': 636.34, 'text': 'this is having higher precedence and the incoming operator is having lower precedence than the operator which is at the top of the stack.', 'start': 628.795, 'duration': 7.545}, {'end': 638.502, 'text': 'then you cannot push it here.', 'start': 636.34, 'duration': 2.162}, {'end': 642.164, 'text': 'first of all, pop out this top of the stack right.', 'start': 638.502, 'duration': 3.662}, {'end': 645.387, 'text': 'then again, check this one with the new top of the stack.', 'start': 642.164, 'duration': 3.223}, {'end': 652.593, 'text': 'now, once you pop out this one and you will append this, or you can say you can print it now, after this one.', 'start': 645.387, 'duration': 7.206}], 'summary': 'Explain stack precedence and operation process.', 'duration': 23.798, 'max_score': 628.795, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI628795.jpg'}, {'end': 735.724, 'src': 'embed', 'start': 699.668, 'weight': 2, 'content': [{'end': 701.129, 'text': 'now check out the precedence.', 'start': 699.668, 'duration': 1.461}, {'end': 702.45, 'text': 'these are having same precedence.', 'start': 701.129, 'duration': 1.321}, {'end': 703.591, 'text': 'now check out the associativity.', 'start': 702.45, 'duration': 1.141}, {'end': 705.553, 'text': 'associativity is what left to right.', 'start': 703.591, 'duration': 1.962}, {'end': 708.194, 'text': 'if left to right, then no need to pop out this thing.', 'start': 705.553, 'duration': 2.641}, {'end': 710.936, 'text': 'simply push the incoming operator.', 'start': 708.194, 'duration': 2.742}, {'end': 712.698, 'text': 'now we have two plus in the stack.', 'start': 710.936, 'duration': 1.762}, {'end': 715.84, 'text': 'right now, after this plus, i have n.', 'start': 712.698, 'duration': 3.142}, {'end': 719.683, 'text': 'so stack would be unaffected, and here we will append this.', 'start': 715.84, 'duration': 3.843}, {'end': 723.199, 'text': 'after n, we have again a strict.', 'start': 721.218, 'duration': 1.981}, {'end': 728.021, 'text': 'now this is having multiplication, is having higher precedence than the top of the stack.', 'start': 723.199, 'duration': 4.822}, {'end': 735.724, 'text': 'right. if higher precedence, then you can simply push it, and this expression would be same.', 'start': 728.021, 'duration': 7.703}], 'summary': 'Explaining precedence, associativity, and stack operations for operators.', 'duration': 36.056, 'max_score': 699.668, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI699668.jpg'}, {'end': 875.561, 'src': 'embed', 'start': 821.379, 'weight': 3, 'content': [{'end': 828.385, 'text': 'pop out the operators from the stack till the stack becomes empty right now.', 'start': 821.379, 'duration': 7.006}, {'end': 830.687, 'text': 'first of all, pop out this plus.', 'start': 828.385, 'duration': 2.302}, {'end': 835.426, 'text': "now i'm writing this here plus.", 'start': 830.687, 'duration': 4.739}, {'end': 836.327, 'text': 'pop out this one.', 'start': 835.426, 'duration': 0.901}, {'end': 838.909, 'text': 'after that, minus, then plus, then plus.', 'start': 836.327, 'duration': 2.582}, {'end': 840.51, 'text': 'right now, stack is empty.', 'start': 838.909, 'duration': 1.601}, {'end': 841.411, 'text': 'now, stop.', 'start': 840.51, 'duration': 0.901}, {'end': 842.712, 'text': 'so now.', 'start': 841.411, 'duration': 1.301}, {'end': 844.753, 'text': 'see, this is not done yet.', 'start': 842.712, 'duration': 2.041}, {'end': 846.615, 'text': 'right now, what you need to do?', 'start': 844.753, 'duration': 1.862}, {'end': 850.097, 'text': 'you have to reverse this expression right.', 'start': 846.615, 'duration': 3.482}, {'end': 857.443, 'text': 'so for reversing what you will do, scan this from right to left, plus, and write down from here plus, plus, minus, plus.', 'start': 850.097, 'duration': 7.346}, {'end': 861.916, 'text': 'now this is the final prefix expression for this.', 'start': 858.675, 'duration': 3.241}, {'end': 864.917, 'text': 'post this infix expression.', 'start': 861.916, 'duration': 3.001}, {'end': 866.738, 'text': 'now this is the conversion using stack.', 'start': 864.917, 'duration': 1.821}, {'end': 873.36, 'text': 'now we will discuss conversion without stack right, and we will compare our answer with this one,', 'start': 866.738, 'duration': 6.622}, {'end': 875.561, 'text': 'whether we are getting getting the same answer or not.', 'start': 873.36, 'duration': 2.201}], 'summary': 'Convert infix expression to prefix using stack and without stack for comparison.', 'duration': 54.182, 'max_score': 821.379, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI821379.jpg'}], 'start': 628.795, 'title': 'Prefix, operator precedence, and conversion using stack', 'summary': 'Covers evaluating prefix expressions, operator precedence and stack operations, and converting infix expressions to prefix using a stack. it includes comparison and examples of stack operations.', 'chapters': [{'end': 723.199, 'start': 628.795, 'title': 'Prefix expression evaluation', 'summary': 'Discusses the evaluation of a prefix expression through the process of comparing and pushing operators in a stack, highlighting the precedence and associativity rules, with examples of popping and appending operators.', 'duration': 94.404, 'highlights': ['The process involves comparing the precedence of incoming operators with the top of the stack and popping out higher precedence operators before pushing the incoming one.', 'The associativity of operators, such as left to right, determines whether an operator needs to be popped out or can be directly pushed into the stack.', 'The evaluation includes examples of pushing, popping, and appending operators in a stack based on the precedence and associativity rules.']}, {'end': 821.379, 'start': 723.199, 'title': 'Operator precedence and stack operations', 'summary': 'Explains the concept of operator precedence and stack operations, including the process of pushing, appending, and popping operators and operands in an expression.', 'duration': 98.18, 'highlights': ["The incoming operator's precedence is compared with the top of the stack to determine whether to push, append, or pop, based on the associativity and precedence of the operators.", 'The process involves checking the precedence and associativity of operators, and accordingly pushing, appending, or popping operators and operands in the expression.']}, {'end': 875.561, 'start': 821.379, 'title': 'Conversion using stack', 'summary': 'Discusses the process of converting an infix expression to a prefix expression using a stack, involving popping out operators and reversing the expression, and later compares the result with the conversion without using a stack.', 'duration': 54.182, 'highlights': ['The process involves popping out operators from the stack until it becomes empty, resulting in 2 plus, 1 minus, and 2 plus operators being popped out.', 'The next step is to reverse the expression by scanning from right to left, resulting in the final prefix expression being plus plus minus plus.', 'The chapter also mentions a comparison with the conversion without using a stack to verify the correctness of the result.']}], 'duration': 246.766, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI628795.jpg', 'highlights': ['The process involves comparing the precedence of incoming operators with the top of the stack and popping out higher precedence operators before pushing the incoming one.', "The incoming operator's precedence is compared with the top of the stack to determine whether to push, append, or pop, based on the associativity and precedence of the operators.", 'The process involves checking the precedence and associativity of operators, and accordingly pushing, appending, or popping operators and operands in the expression.', 'The process involves popping out operators from the stack until it becomes empty, resulting in 2 plus, 1 minus, and 2 plus operators being popped out.', 'The next step is to reverse the expression by scanning from right to left, resulting in the final prefix expression being plus plus minus plus.', 'The chapter also mentions a comparison with the conversion without using a stack to verify the correctness of the result.', 'The associativity of operators, such as left to right, determines whether an operator needs to be popped out or can be directly pushed into the stack.', 'The evaluation includes examples of pushing, popping, and appending operators in a stack based on the precedence and associativity rules.']}, {'end': 1444.431, 'segs': [{'end': 940.038, 'src': 'embed', 'start': 896.196, 'weight': 0, 'content': [{'end': 899.739, 'text': 'so first of all, solve this one, convert this into prefix.', 'start': 896.196, 'duration': 3.543}, {'end': 902.001, 'text': 'what should be the prefix here?', 'start': 899.739, 'duration': 2.262}, {'end': 905.344, 'text': 'this operator should be before these operands.', 'start': 902.001, 'duration': 3.343}, {'end': 910.221, 'text': 'so this this is now a prefix of this one.', 'start': 905.344, 'duration': 4.877}, {'end': 912.102, 'text': 'so this is now one operand.', 'start': 910.221, 'duration': 1.881}, {'end': 914.044, 'text': 'this complete will act as a operand.', 'start': 912.102, 'duration': 1.942}, {'end': 919.148, 'text': 'now. next, although this, this is the operator which is having second highest.', 'start': 914.044, 'duration': 5.104}, {'end': 924.312, 'text': 'but this thing we have already solved, because this is within these parenthesis, this operator right.', 'start': 919.148, 'duration': 5.164}, {'end': 930.034, 'text': 'so now, after this, we have this multiplication and divide.', 'start': 924.972, 'duration': 5.062}, {'end': 931.855, 'text': 'these are having higher precedence.', 'start': 930.034, 'duration': 1.821}, {'end': 935.956, 'text': 'so now here both multiplication and divide, both are having same precedence.', 'start': 931.855, 'duration': 4.101}, {'end': 937.917, 'text': 'so check out the associativity.', 'start': 935.956, 'duration': 1.961}, {'end': 940.038, 'text': 'associativity is left to right now.', 'start': 937.917, 'duration': 2.121}], 'summary': 'Solve expression, convert to prefix, consider associativity. multiplication and divide have same precedence and left-to-right associativity.', 'duration': 43.842, 'max_score': 896.196, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI896196.jpg'}, {'end': 1356.271, 'src': 'embed', 'start': 1314.845, 'weight': 3, 'content': [{'end': 1319.947, 'text': 'you need to or you can say the compiler need to scan this infix expression multiple times.', 'start': 1314.845, 'duration': 5.102}, {'end': 1327.133, 'text': "it's not like that in one scan only you can get this prefix, as i guess you have analyzed here, but in when you are using stack.", 'start': 1319.947, 'duration': 7.186}, {'end': 1332.579, 'text': 'in that case compiler need to scan only once this expression from left to right, right.', 'start': 1327.133, 'duration': 5.446}, {'end': 1335.462, 'text': "so now it's up to you which approach you are going to follow.", 'start': 1332.579, 'duration': 2.883}, {'end': 1344.207, 'text': 'so now i guess no need to write down the rules here, because if you get it how to convert this into this, you can write down the steps,', 'start': 1335.462, 'duration': 8.745}, {'end': 1351.349, 'text': 'because obviously i am going to write down the steps only, and if you know how to convert it right, so you can easily write down those steps.', 'start': 1344.207, 'duration': 7.142}, {'end': 1356.271, 'text': 'first of all, reverse the synfix expression right, then scan it from left to right.', 'start': 1351.349, 'duration': 4.922}], 'summary': 'Compiler needs to scan infix expression once with stack for conversion to prefix.', 'duration': 41.426, 'max_score': 1314.845, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI1314845.jpg'}, {'end': 1444.431, 'src': 'embed', 'start': 1436.625, 'weight': 5, 'content': [{'end': 1438.666, 'text': 'you can say that prefix expression.', 'start': 1436.625, 'duration': 2.041}, {'end': 1440.047, 'text': 'fine, so now, next video.', 'start': 1438.666, 'duration': 1.381}, {'end': 1442.469, 'text': "i'll discuss with you about binary search trees.", 'start': 1440.047, 'duration': 2.422}, {'end': 1443.53, 'text': "right, so i'll see in the next video.", 'start': 1442.469, 'duration': 1.061}, {'end': 1444.431, 'text': 'till then, bye, bye, take care.', 'start': 1443.53, 'duration': 0.901}], 'summary': 'Discussion on binary search trees in next video.', 'duration': 7.806, 'max_score': 1436.625, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI1436625.jpg'}], 'start': 875.561, 'title': 'Converting infix expressions to prefix notation', 'summary': 'Discusses expression precedence, conversion to prefix notation, and converting infix expressions to prefix expressions without using a stack. it emphasizes the importance of parenthesis, operator associativity, and the need for multiple scans. it also mentions the discussion of binary search trees in the next video.', 'chapters': [{'end': 940.038, 'start': 875.561, 'title': 'Expression precedence and prefix conversion', 'summary': 'Discusses the precedence of operators in an expression and demonstrates the conversion of an expression to prefix notation, emphasizing the importance of parenthesis and the associativity of operators.', 'duration': 64.477, 'highlights': ['The parenthesis are highlighted as having the highest precedence among all the operators present in the expression.', 'Demonstrates the conversion of the expression to prefix notation, emphasizing the positioning of operators before operands for prefix formation.', 'Explains the precedence and associativity of multiplication and division operators, highlighting their equal precedence and left-to-right associativity.']}, {'end': 1444.431, 'start': 940.038, 'title': 'Converting infix to prefix', 'summary': 'Explains the process of converting infix expressions to prefix expressions without using a stack, emphasizing the need for multiple scans in contrast to a single scan with a stack, and concludes with a mention of discussing binary search trees in the next video.', 'duration': 504.393, 'highlights': ['The chapter emphasizes the need for multiple scans when converting infix expressions to prefix expressions without using a stack, as opposed to a single scan requirement when using a stack.', 'It explains the process of converting infix expressions to prefix expressions, highlighting the steps of reversing the infix expression, scanning from left to right, checking and comparing precedence and associativity rules, and the importance of reversing the resulting expression.', 'The chapter concludes with a mention of discussing binary search trees in the next video.']}], 'duration': 568.87, 'thumbnail': 'https://coursnap.oss-ap-southeast-1.aliyuncs.com/video-capture/8QxlrRws9OI/pics/8QxlrRws9OI875561.jpg', 'highlights': ['The parenthesis are highlighted as having the highest precedence among all the operators present in the expression.', 'Demonstrates the conversion of the expression to prefix notation, emphasizing the positioning of operators before operands for prefix formation.', 'Explains the precedence and associativity of multiplication and division operators, highlighting their equal precedence and left-to-right associativity.', 'The chapter emphasizes the need for multiple scans when converting infix expressions to prefix expressions without using a stack, as opposed to a single scan requirement when using a stack.', 'It explains the process of converting infix expressions to prefix expressions, highlighting the steps of reversing the infix expression, scanning from left to right, checking and comparing precedence and associativity rules, and the importance of reversing the resulting expression.', 'The chapter concludes with a mention of discussing binary search trees in the next video.']}], 'highlights': ['The method aims to minimize the number of scans required to solve the problem, as scanning the expression multiple times is described as time-consuming and lengthy.', 'The process involves scanning the reverse infix expression from left to right, pushing operators onto a stack and printing operands to obtain the prefix expression.', 'The chapter discusses the efficient algorithm of converting infix to prefix using a stack, presenting the process and rules, and highlighting the various approaches to achieve the conversion.', 'The process involves evaluating operators, checking precedence and associativity rules, and manipulating the stack.', 'The rule for pushing and popping parentheses into the stack is different based on whether it is an opening or closing parenthesis, with the reverse rule applied when it comes to handling closing parentheses, emphasizing the importance of understanding the specific rules for each type of parenthesis.', 'The process involves comparing the precedence of incoming operators with the top of the stack and popping out higher precedence operators before pushing the incoming one.', 'The parenthesis are highlighted as having the highest precedence among all the operators present in the expression.', 'The chapter emphasizes the need for multiple scans when converting infix expressions to prefix expressions without using a stack, as opposed to a single scan requirement when using a stack.']}