Check for balanced parentheses using stack

See complete series on data structures here:
• Data structures
Algorithm or program to check for balanced parentheses in an expression using stack data structure. This is a popular programming interview question.
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[@20mymysf]

I clearly understand this subject now. I saw this for free and am in debt from school for something they couldn't teach. The irony. Thanks for the lovely video!!

[@higlights2938]

H

[@selenayyalcn8221]

the best data structures video on the internet i've ever seen. thanks for the clarity and understandability even 9 years later. hope you're okey

[@suvansingh3684]

The best explanation of this concept , Last Un-Closed , First Un-Closed , makes it clear why a stack must be used. This detail has been left out it most explanations. Great work. @9:27

[@abocidejofa9686]

No one can explain any clearer that this!!! thank you

[@tejasrawat1337]

your classes are very interactive as programming perspective. I could say this is the best data structure tutorial till now we have in web.

[@poseidon2735]

This guy is one enough to make learn coding the whole student community

[@rebelutionarygaming8875]

I've learned more abuout data structures from your videos, than I have from school. Thank you.

[@dephc0n1]

Thank you for this explanation. I have to do this exact problem for a job interview coming in the fall.

[@rohanbangash5827]

4 years later, how did it go lol

[@dephc0n1]

@@rohanbangash5827 Nailed this question on every interview. Funny enough I work for a company that did not ask this question. It's a great algorithm to help think about the benefits of a stack data structure.

[@aswin2pranav]

You're a bloody genius... Thanks!

[@eklavyaprasad5009]

Remembering Lord Harsha ❤️

[@neelanshsharma275]

I'm really grateful sir, I will forever remember you. Thank you from the bottom of my heart ❤

[@drkato9]

Your classes are all fantastic. Thanks so much!!!

[@DineshKumar-lq2ck]

Words are short to express my gratitude. I am able to code it in C# with your advised alsogrithm, it works in all conditions. Thank you once again.

[@plsjustinit]

Wow, exactly the same as what I did in an Amazon phone interview. I forgot to check s.isEmpty while peeking the stack until it threw exception in one testing, but after adding it back, it is exactly the same as what it shows here. Cool!

[@nikunjchapagain5654]

did you get the job tho?

[@muhammadbilalmalik7292]

@@nikunjchapagain5654 yes he was refrenced by me !!

[@davidechiappetta]

using a stack seems a bit excessive to me, since for each character to match it must make a call to the C ++ library and this consumes cpu and memory, you can simply use a byte array of fixed length, as large as the number of characters or symbols to compare, in which in each element you can save a number corresponding to the character to be balanced, e.g. 1 corresponds to square brackets and 2 corresponds to round brackets and a global pointer which moves to the right (g_ptr ++) to insert char x,y,z and to move to the left (g_ptr--) to compare and remove char z,y,x , (if the characters do not match or if the pointer goes below zero then there is an unbalance) a method that can also be used to keep track of the states of C directives (for example excluding everything that descends from #else (including other #if #else #endif and resuming the block at the exit of the first #endif) where it is not worth using a stack or a parser e.g. LALR

[@ighsight]

Your comment is overkill, like the whole point was to show you know as much as the presenter. The video is teaching how to use an important data structure, all your extra talk about efficiency and libraries is irrelevant. Developers seeking jobs need to know what a stack is and how to use it. Period. Understanding limitations of data structures and their accompanying algorithms IS important, but there’s no need shoehorn that in to a basic introductory video where folks are just learning how to use the structure.

[@rhugvedisali9123]

Easy to understand teaching

[@hemantyadav1047]

We can maintain two data structure stack and queue. stack for the opening and queue for the closing parentheses. The we can compare these two if all the parentheses are in the order.

[@parasdesh]

I’ve been asked this question in coding interview.

[@vedangkavathiya8426]

Sir your explanation is too good thanks for explaining me this topic of stack... 😃

[@mdkaif-kf7oh]

You have the best way of teaching..🔥🔥🔥

[@aakashmudigonda3375]

if anyone requires the "C" code for the above program :: #include #include #include #define MAX 100 struct Node{ int data; struct Node* next; }; typedef struct Node node; node* top = NULL; // PUSH() void Push(char c) { node* temp = (node*)malloc(sizeof(node)); temp->data = c; temp->next = top; top = temp; } // POP() void Pop() { node* temp; if (top == NULL) { return; } temp = top; top = top->next; free(temp); } int isMatching(char c){ if ( top->data == '(' && c == ')' ){ return 1; } else if ( top->data == '[' && c == ']' ){ return 1; } else if ( top->data == '{' && c == '}' ){ return 1; } else return 0; } void isBalanced(char exp[], unsigned long len){ for (int i = 0; i

[@dharshanaapiskala7558]

TQ so much !!!!

[@kritikashukla9937]

So smoothly explained. Thank you!

[@bhaktitarang04]

I am really grateful to the person for this awesome compilation of Data Structures Thanks You!

[@prashantbajpai2142]

good work sir thnk u so much fr make a awesome creation of videos u r the real teacher thnks a lot sir plz upload more videos related to Tree,Graphs,Constructor,exceptional handling,file handling etc

[@raghulg6155]

Much smaller code in C: // Check for paranthesis using stack and the stack here is implemented using Linked lists #include #include #include int flag = 0; struct Node{ int data; struct Node *link; }; struct Node *head; void push(int x) { struct Node *nod=(struct Node*)malloc(sizeof(struct Node)); nod->data=x; nod->link=head; head=nod; } char pop() { char n; struct Node *temp=head; if(head==NULL) return; n=temp->data; head=head->link; free(temp); return n; } void checkforparanthesis(char *A,int x) { char c; for(int i=0;i

[@lamle5183]

You make it sooo easy to understand. Thanks a lot!

[@faizannisar1515]

amazing lectures as well as brilliant voice

[@Hyperflow]

thank you for this input method, made it way easier for me to understand

[@JangBahadur3028]

Really awesome and helpful explaination. Thanks.

[@nooreldali7432]

my exam is in two hours you are lifesaver

[@prashantdiwakar1302]

Beautiful Explanation

[@danielsenik2432]

thanks, this video helped a lot to understand the general idea of the algorithm

[@raedkhader6263]

I cant thank you enough, so simple and clear ;)

[@indavarapuaneesh2871]

Excellent marvellous extraordinary mind blowing fantastic awesome.no words to describe your work.thanks guruji

[@Mohit-nw5jr]

you r the god of data structures!!! thanks a lot! BTW where are u from in India??

[@liam190]

It definitely seems like it. Indians are generally very good at programming anyways.

[@kyssl]

Liam he's from India and he died in 2015

[@goodToBeLost]

Sid He died in 2015? You mean him or the person he founded My Code School with, Harsha Suryanarayana? He's the one who unfortunately passed away in 2014 or so right? This person is Animesh Nayan and he is pretty much alive?

[@kyssl]

Amrita Basu i was talking abt Harsha

[@goodToBeLost]

Sid So Harsha created these videos ? I was under the impression that it was Animesh.

[@brando8045]

excellent video! i understand this concept much better now.

[@GGlearn]

thank you a lot . you are a great teacher

[@pramodbhat6314]

The best explanation.

[@samarthkhatwani]

hats off bro... thank you so much for this amazing series

[@hanadotexe]

thank u very much, very well explained! helped me a lot.

[@AshishMenon1997]

if length of the string is "odd" its invalid , only we should check for the even ones.

[@brahmkaransingh8804]

If the length is odd you should simply return false as there is no chance of matching of brackets

[@Raven_SG]

Thanks for the help! really help me alot in my studies! !

[@rinjakundu]

Nicely explained! Really helpful

[@yassinedownpourz]

// C code Implementation: #include #include #include #include typedef struct stack{ char data; struct stack *next; } stack; stack *push(stack *top, char chart){ stack *new = malloc(sizeof *new); new->data = chart; new->next = top; return new; } stack *pop(stack *top){ if(!top) return NULL; stack *temp = top; top = top->next; free(temp); return top; } char Stack_top(stack *top){ if(!top) return '\0'; return top->data; } bool isEmpty(stack *top){ return !top ? true : false; } bool isPair(char op, char ed){ if(op == '(' && ed == ')') return true; if(op == '[' && ed == ']') return true; if(op == '{' && ed == '}') return true; return false; } bool balanced_parantheses(char str[]){ stack *tmp = NULL; for(size_t i = 0; i < strlen(str); i++) { if(str[i] == '(' || str[i] == '{' || str[i] == '[') tmp = push(tmp, str[i]); else if(str[i] == ')' || str[i] == '}' || str[i] == ']') { if(!isEmpty(tmp) && isPair(Stack_top(tmp), str[i])) tmp = pop(tmp); else return false; } } return isEmpty(tmp) ? true : false; } int main(void){ char str[] = "{()((((("; balanced_parantheses(str) ? printf("Balanced") : printf("NOT Balanced"); }

[@jitenkhatri8001]

Happy teacher's day bro

[@rownitakhanam5013]

By mercy of Allah,you 're saving careers of a lot of people.

[@cyberpsybin]

stfu

[@rpitpatel1004]

Amazing explanation Thank you sir

[@ishrattonny6094]

Great explanation !

[@maycodes]

Thank you , what a great contribution.

[@sbk1398]

excellent explanation

[@pachavamanasa5833]

thanku you so much sir you are healping us a lot

[@aymardeoolatounde]

Hi Sir, I think after set variable n with expression length, we can check if n is even. If it’s not, n is odd and return false (Expression will contain only brackets).

[@bhawnakukreja7589]

great explanation sir...thanks a lot

[@nands4410]

What are some more popular programming interview questions like this one?

[@animefreak0514]

In the about section of his channel he has a link to an article about programing interviews.

[@nands4410]

Christian Jusino that too is outdated but

[@subforsubcommunitycenter6961]

Wow u have all the thing i searching for

[@ChandraShekhar-by3cd]

Amazing Video..please upload some more videos on Interview Questions and MultiThreading and Design Pattern

[@southpeng]

Very clear instruction!

[@user-ox1dr3ec7m]

Thank you this really helped! c:

[@sagarmittal9998]

Nice explanation👍👍

[@diksha5746]

Thank you. It was very helpful

[@naveedachkal9734]

helpfull should have c version also

[@Kalpeshsoni]

gist.github.com/mycodeschool/7207410

[@virajdoshi]

Why would you use stack to 'park' the parantheses ? how is the possibility of any bracket finding a match within the 'parked' list/array ? Dosen;t the pop method give you always the topmost (last) instance ?

[@Arundevvb1]

Thank you.

[@kasyapdharanikota8570]

best explanation

[@tharugeethz6021]

Thank u so much! It was really helpful !

[@shashwatsingh2793]

Great video sir

[@u2lover10]

pseudo code rocks! Thanks!

[@mdsolaimanchowdhury627]

It was really helpful !

[@Skrafutae]

Nicely explained :)

[@aymensekhri2133]

Thanks a lot, very helpful

[@saurav4180]

great job sir....

[@chayankanungo4778]

Thank you so much Sir!

[@santgupta357]

Nice videos. To the point and easy to understand. Where can I get code if I want ?

[@mayursatbhai1624]

Sant Gupta open "see more" below the video and click on "see source code here.

[@chennasreenu4723]

best of data structures

[@slightlygruff]

Thanks so much!

[@chanduseshadri]

I would add this piece of code, if(expression.length() % 2 != 0){ return false; } in the beginning, anyway good video :)

[@chanduseshadri]

+Prem Kumar Hi Prem, Thanks for the answer. That piece of code I wanted to add would only fit if the expression contains no other characters except parentheses (could be any closing ones "''" too). Since the video was only mentioning a string with parentheses, I considered that would fit in there. Yes, if the string can include all sorts of characters, as you said that won't work. Thanks for taking your time anyway :)

[@kanishkjain2767]

nice logic it will reduce the time and space complexity for odd cases to a great extend

[@rohanmehto7609]

when in use, we dont check for expressions which only contain paranthesis (thats stupid) , so the expression with odd length can have balanced pararenthesis.

[@ibrahimshaikh3642]

Many many thanks,keep it up

[@rawan8432]

so clear , thanks alot

[@kmahesh-eq4ji]

the given code in the git hub will fail for the test case when we include the space in the user input because the taking of string input will not execute after a blank space I'm still having doubt on the concepts of strings and characters of user input oriented.. i will also do silly mistakes like this code which was uploaded on git hub

[@seraj_valley]

u r legend sir

[@kcmag1k]

superb!!

[@usama57926]

thank u brother

[@xof8256]

Thank You

[@k.kirankumar2153]

Thank you

[@Abhishekjha-rr2nm]

thanks

[@MB-sk6oc]

It was Helpful :)

[@rajdeepkhandelwal1653]

thank you 🙌

[@aarb17]

Great, thank you

[@imaadnaeemansari8693]

thank you sir!

[@daoanhtuandao8106]

thank you so much

[@manassrivastava6452]

This reminds me of Push Down Automata(PDA)

[@GamjaField]

How do I deal with the brackets inside the quote, or comments?

[@shahriarbadhon4596]

Just awesome

[@trishachander1602]

what's the algorithm to check that the top doesn't pair with i?

[@xahidsakib8346]

HELPFUL

[@memofahood4543]

Amazing explanation :)

[@daswarudo1957]

thanks!

[@khaltoumach1243]

What does POP () function do

[@ralphmente3988]

Thank youuu!!!

[@YogaandLivingwithChai]

Can you solve for String Anagram and word ladder?