String permutation algorithm | All permutations of a string

This lecture explains how to find and print all the permutations of a given string. This lecture involves two example explanations followed by code logic explanation for printing and finding all permutations of a string. If you find any difficulty or have any query then do COMMENT below. PLEASE help our channel by SUBSCRIBING and LIKE our video if you found it helpful...CYA :)
CODE LINK: drive.google.c...

[@techdose4u]

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[@prashantagarwal8877]

I always had a fear when it comes to find permutation, you have explained it in a very simple way. Thanks a lot!!!!

[@lancema2894]

Very clear explanation. Finally understand why we need the backtracking after the recall of permute. Thank you very much.

[@techdose4u]

Welcome :)

[@faizanzahid490]

Those who have tried coding knows the complexity of outputs for this case where elements of string is not repeating Thumbs up bro

[@techdose4u]

Thanks :)

[@mitchellbaylor8132]

Pro trick : you can watch series at flixzone. Me and my gf have been using it for watching lots of of movies these days.

[@graysonalan44]

@Mitchell Baylor Definitely, have been watching on flixzone} for months myself =)

[@hectorotis512]

@Mitchell Baylor Yup, been watching on Flixzone} for years myself :)

[@alexanderamos9961]

@Mitchell Baylor yup, have been using Flixzone} for since november myself :D

[@rhishishrivastava675]

You are a magician, you can make someone believe in himself/herself and not give up on dreams. God bless you.

[@aayushsugandh4036]

This perhaps used to be one of those problems, which I always use to try in my school life, but could never solve it using for loops, but now in grad life, it has changed!

[@techdose4u]

:)

[@vcfirefox]

Love it. Time and time again, I come back to your channel when I need a REALLY good grasp of something that is not explained well in leetcode. Thank you!

[@shreyasvishwakarma8979]

Today is 2022 and you made this in 2019 . Like 3 year still 96.2k subscribers . You deseve 1M sadly you and i know indians love clickbait stuff . 96.2K shows you are best at teaching not at Clickbait . Keep up the good work sir : )

[@techdose4u]

Thanks 😊

[@asmartguycodename4721]

Shut up goofball

[@JayDonga]

Your explanation of the permutation problem is better than most other explanations on the Internet.

[@techdose4u]

Thanks :)

[@swapnil1108]

I saw this video and went on to explore your playlist and finally subscribed you..LOL. Awesome explanation. I wish you had a second part with DUPLICATE STRINGS.

[@techdose4u]

Will do it later. I am loaded with question requests now :)

[@siddhi1993]

This is very helpful for me. Thank you. Very good presentation. Now I totally understand the string permutation. The dry run of algorithm is very helpful and impressive.

[@techdose4u]

Thanks :) glad that you understood

[@bitbyte8177]

Dude you know what, your method is the most intuitive method I have seen on youtube. Awesome job!!

[@techdose4u]

Thanks :)

[@nagalakshmichithambaranath1147]

Yes true.

[@bhimsendabby]

I always confused with permutation, I mean how to implement permutation in coding but after your explanation, I got the logic of how to code this thank you Sir.

[@techdose4u]

Welcome

[@bhimsendabby]

@@techdose4u thanks a lot

[@cityhunter1477]

Thank you! I saw so many blogs and videos with the tree and the code separate. Yours was the first to connect the tree to the code directly! Now I can understand what the swaps are doing exactly and how the iteration works.

[@techdose4u]

Nice 😊

[@olgyish]

I was able to code this easily after watching your explanation. That was a great explanation.

[@techdose4u]

Nice 😊

[@m.p.3688]

I watched NeetCode explenation of this problem probably 5 times and could not understand how logic behind it actually relates to code solution. Watching this explenation helped me understand code behind the solution instantly, because logic presented in drawning explenation is simple and actualy demonstrates code logic.

[@feelgood0108]

awesome explaination sir.Now I got clear understanding on what is backtracking.Thank you so much

[@jithiny6953]

Very nicely explained. I saw many videos to understand this, but this was super clear

[@ashutoshbichare]

Easier is(without swapping): def permut(str,k): if len(str)==0: print(k) else: for i in range(len(str)): permut(str[i+1:]+str[:i],k+str[i])

[@rohit210995]

I think this method won't work for duplicates. It will count the duplicates as separate characters. Eg.- ABAC. In this case total no. of permutations possible would be 12 (4!/2!). However, if we follow this method it will end up 24 (4!) combinations, simply because it counts the first and the second occurrence of A as different alphabets. Meaning - in ABAC, if A in the first place is swapped with A in third place we end up with the same string ABAC, whereas the above logic treats them as different. (This can be taken care of if we use a counter for each character).

[@gkeranna3543]

If you want to remove duplicates. just you will add all Strings into HasSet.

[@georgesaab7609]

store all results in a vector of strings and then youd be able to filter the duplicates

[@Goku-ri3tl]

Amazing!! This worked like a charm )) at my first try I have been trying for many days different tutorials but no one explained as good and easy as you, Thank you so much

[@techdose4u]

Great :)

[@aadridanand]

from all the explanation this is one of the most easiest way one can explain,thanks👏👏

[@debasishpatnaik294]

Finally Understood it..thanks a lot for the detailed explanation of the algo..

[@techdose4u]

Nice :)

[@sunilkumaryadav3194]

This is for the first time I try to understand it and You nailed it. Thank you

[@amitavamozumder73]

if your string is not called by reference (immutable) then you don't need to do that backtrack thing right? FOr some reason, this method doesn't work or JS, no idea why.

[@ozzyfromspace]

I forgot how to write permutations but need to write such an algorithm for a project I'm doing in recreational maths. Thanks for explaining it :) I was thinking "recursion" so I'm glad you did that approach. I'm gonna write something up in python now

[@techdose4u]

Good luck

[@UnknownLearner-od3qn]

your videos are always awesome and ofcourse so much informative & easy to understand ... Thnx 🙏🙏

[@user-ok4fx3kl6f]

By far the best explanation of this problem on you tube. Thanks much!

[@shivamgupta3293]

Everytime I found best explanation only in this channel. Thanks Man

[@techdose4u]

Welcome :)

[@gpavansai7207]

Thank You so much, your lecture is very clear and elaborative.

[@urvashisharma7415]

interview in 20mins...thank god i watched this

[@techdose4u]

You got it!!

[@urvashisharma7415]

@@techdose4u thank u so much for the reply 😭

[@urvashisharma7415]

@@techdose4u Update: I got placed 😭

[@thesadanand6599]

I am floored, dude u earned a sub...

[@techdose4u]

Thanks :)

[@sakethram327]

i think the code works even if we remove the last swap().does it cause any anomalies?

[@lucasbollella8487]

Thanks man, this video is really clear.

[@techdose4u]

Glad it helped!

[@saisrisai9649]

The best tutorial ever..

[@techdose4u]

Thanks :)

[@SomnathDas-fg2qc]

Sir i haven't understood what is the need of second swap function, if we didn't write then also it will backtrack go to original string that is ABC?

[@vishnu_goud18]

Very clear explanation. But what if length of string is more like let's say 10 does it leads to TLE?

[@swanhtet1]

This is the best explanation on this problem.

[@goku_kadhir]

Hi, Can any one tell how this swap function works in C++... swap((a+l), (a+i)); I am not familiar in c++ and so I don't understand why we are passing the char array (a) + int (index l / i) in swap function

[@OP-yw3ws]

This explaination is so easy to understand, thankyou!

[@rutachaudhari5774]

Thank you so much, your explanation is very easy than others. Its very difficult to understand permutation with recursion, but this makes it easy

[@techdose4u]

Thanks 😊

[@SkKarmakar-du5nu]

Sir,in this process 5 objects permutation is not getting,only 30permutatiin is gotten ,kindly show the tree diagram of 5 objects i,e a,b,c,d,e

[@ChandraShekhar-by3cd]

The visualization technique is quite helpful in understanding the algorithms .. Thanks a lot TECH DOSE :)

[@techdose4u]

Thanks

[@adithyakiransekar]

How can we implement this for string having duplicates?

[@jimmy-dk9lo]

My mind is exhausted, but still I am able to understand, thanks a lot.

[@techdose4u]

Welcome :)

[@algotorials81]

swap(a+l,a+i); permute(str,l+1,r); if [l=0, i=0 A-A swaps] , [ l=1, i=1 B-B swaps] , [l=3, i=3 and so C-C] should swap ? at 2:31 as l changes on each recursive call so do i. How is it getting swapped i cannot catch ?

[@harshpanwar1550]

Beautifully Explained Sir...Thanks a lot!!!

[@samudrasen2935]

Really wonderful explanation .all the doubts in string permutations got cleared.

[@idontusecryptocurrency5870]

Thanks sir.Your video was very good for a beginner

[@techdose4u]

Great ❤️

[@duyle-ui4ul]

Best explaination I've ever took. Really appriciate it!

[@kartikenbarnwal]

😍thak gya hu vro iski video like kr krke

[@techdose4u]

:)

[@Ashok-oe3lo]

really a great explanation and its easy to understand...thanks for all your time. It will be helpful if you can also explain how to handle if the character is duplicate. Thanks

[@techdose4u]

Yea you are ryt. This doesn't handle duplicate characters. I will try to make this case in future.

[@markovujanic]

wow, this is very well explained, especially I liked how you wrote on branches swapping you do. Thanks a lot

[@vengateshwarang]

Awesome, thanks for the good explanation

[@TOMGAMING-hy9hi]

Comment to banta hai boss for your explanation.....

[@techdose4u]

Thanks

[@jayakumarc9663]

Good explanation Indeed :) But i have one doubt, why would prefer second "Swap" under for loop and that you saying backtracking. But when i ran without second swap, it produces same results with also natural order of Input. Could you please make me understand of importance of that second swap ?

[@GorelikS]

Try to run 'ABCD' and you should see why you need the second swap

[@brkekr]

Think of the string 'ABC' , you are first swapping A with A (as told) and you are doing the recursive permutation for the left string 'BC' and you are doing the same till you print 'ABC' and 'ACB' respectively. At the very end you have the string 'ACB' and your left value is 1, and you have to make this string 'ABC' back to continue with the swap of A and B. So you swap left (which is 1) and the value of i (which is 2) to get the initial string 'ABC' back. I hope I could tell :)

[@brkekr]

Btw you are naturally doing the backtracking for making ABC to ACB.

[@gepliprl8558]

@Burak. Thank you so much man. Your explanation really helps me.

[@brkekr]

@@gepliprl8558 No problem!

[@prateekrajput2646]

you explained with god level

[@techdose4u]

Thanks :)

[@mallikarjunpidaparthi]

Wow... Clear explanation thanks brother : )

[@techdose4u]

Welcome

[@priyanshuchaurasiya6184]

Thanks a lot♥♥ , your explanation is so good the just looking at your pseudo code I am able to code the problem.😊😊

[@bowenyi-kj3vr]

This is a great explanation!!!!!!

[@abhinayrevuru5428]

Very Good Explanation Bro!!!, but i am not clear on the line 'permute(a,l+1,r)',could you please help me in understanding.

[@techdose4u]

Because we are fixing the current char and we want to permute for the rest of the string on right (by fixing current character).

[@abhinayrevuru5428]

thanks Bro, so using +1 to fixing the character..

[@b_rza]

Great explanation. Thank you very much

[@techdose4u]

Welcome 😁

[@ranusingh862]

Best explanation I could ever get. 👏

[@myyoutubeisthis]

thank you very much sir for this explanation

[@rakshitsingh7504]

Thank you for explaining it, best of all I have seen.

[@techdose4u]

Welcome :)

[@adityaojha2701]

Thanks a lot sir. You explained very well!!

[@techdose4u]

Welcome ☺️

[@user-wt2dq5yt9h]

good explanation but I need to implement it using for loops not recursive functions (it is more complex)

[@tanusrisaha4873]

Finally understood recursive tree...awesome explanation..going to watch ur full playlist :)

[@techdose4u]

Thanks :)

[@uttarandas8113]

1:15 what you need to understand!!! Thanx sir! I don't know why was this video not on top of suggestions =(

[@kunjanshah_sr]

public class Permutations extends Activity { String TAG = Permutations.class.getSimpleName(); char[] Res; int[] A; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); String input="ABC"; Res = new char[input.length()]; A = new int[input.length()]; perm("ABC".toCharArray(), 0); } void perm(char[] str, int k) { if (str.length == k) { Log.d(TAG, Arrays.toString(Res)); } else { for (int i = 0; i

[@irfadkp9362]

whats 'a' in code

[@justanotherlearner1404]

bhai bahut easily explain karte ho ......thank you so much

[@techdose4u]

Welcome

[@harryhenderson3636]

Inspired by Wikipedia I have developed my own method of generating permutations which is similar to this - they might actually be the same thing. Here's how mine works. Suppose we have ABCD - the situation would look like this: 1 ABCD Now repeatedly copy line 1 and move B to the left until it can't move anymore. So we have: 1 ABCD 2 BACD Now we move on to C. Now we have to copy both lines 1 and 2 and move C. 1 ABCD 2 BACD copy of line 1 moving B 3 ACBD copy of line 1 moving C 4 CABD copy of line 1 moving C Now that C is all the way to the left we start copying line 2. 5 BCAD copy of line 2 moving C 6 CBAD copy of line 2 moving C C is all the way to the left again but now we have to change characters or we will get duplicate permutations. Whenever we change a character we start copying line 1 again. If you study the permutation list numbers you will notice the character changes take place based on the factorial numbers: 1!, 2!, 3! = 1, 2 and 6. Starting on line 2 we begin moving B, on line 3 we start moving C and on line 7 we start moving D. Subtracting 1 from these numbers gives us 1, 2 and 6. Here is my example extended to make sure the pattern is clear. 1 ABCD 2 BACD copy of line 1 moving B 3 ACBD copy of line 1 moving C 4 CABD copy of line 1 moving C Now that C is all the way to the left we start copying line 2. 5 BCAD copy of line 2 moving C 6 CBAD copy of line 2 moving C 7 ABDC copy of line 1 moving D 8 ADBC copy of line 1 moving D and so on...

[@RajnishSingh-tw4tu]

Hey the code which u have provided in description doesn't handle duplicate character. Meaning if string is ABC then its perfect but if its ABB then it will repeat few of the string

[@UnknownLearner-od3qn]

It's always be confusion that height of the tree is number of levels -1 or number of levels......... 1 / 2 by seeing it looks like height is one although levels are two ...... What is exact definition of height of tree?

[@nagalakshmichithambaranath1147]

The best explanation.

[@techdose4u]

Thanks :)

[@jaskiranmalhotra989]

This is actually the best explaination thnx alot sir.

[@physicsmathsworld2033]

What is 'a' here ??

[@mr-engin3er]

Good explanation. Thanks for sharing. Keep it up. All the best for your future.

[@debanjanpradhan7633]

Great Explanation, Thanks a lot!

[@techdose4u]

Welcome :)

[@jugsma6676]

This is so much clear explanation indeed.

[@techdose4u]

Thanks

[@pawanlok1776]

thank you , this video help me a lot to understand the topicc

[@kanhashukla6265]

Thanks for the efforts man. This helps a lot. Keep up the good work.

[@techdose4u]

Welcome :)

[@shubhampandey7177]

good explanation. It really helped!!!

[@techdose4u]

Welcome :)

[@hackerstec5136]

I have confusion with regard to L For string ABC wont the value of L go above 3 After moving from bottom to top Since l is incremented in every function call

[@varunmalhotra6652]

sir can u elaborate on thought process how u develop the code... by making tree and developing code simultaneously

[@techdose4u]

This is the pattern for recursion. Practice some recursion programs and this will be very easy.

[@shailendrakk6226]

Awesome explanation.Loved it

[@techdose4u]

Thanks :)

[@LegitGamer2345]

FINALLY UNDERSTOOD!!!!!!

[@techdose4u]

Nice :)

[@seetharaman6603]

You are great. Nice and thank-you

[@anuragalvala2113]

Bro can you explain the code when we have duplicates in the string but we only need unique permutations as output

[@shivamsehrawat7610]

In java you can use a set as it only permits unique values

[@wolfgaming8690]

before passing the input string in the function sort function to sort the string, next void solve(string s,int l,int r) { if(l==r) { cout

[@priyasuhag6798]

salute you sir, thanks you so much to make it

[@anupkulkarni705]

Why do you need a second swap function? It should work same without second swap function. I may be wrong but worth checking.

[@debashisdas6593]

very good explanation !!

[@mits564]

I have one doubt In swap((a+l), (a+i)). What is in (a+l)? Here a is string and l is integer how we can add that?

[@glazeds0n]

very good explanation,,, as always

[@techdose4u]

Thanks

[@kushalappaca5324]

Excellent explanation! Great work👌👌

[@techdose4u]

Thanks

[@kushalappaca5324]

@@techdose4u I have one doubt though.... Why do we need the second swap function? It works without that too... Recursion works that way right?

[@poojithakuruganti9868]

Thank You,but my doubt is why permute function has a,r

[@suryakangeyan9751]

just found this gem :) , subscribed !

[@techdose4u]

Thanks :)

[@eugeneyap4208]

Love the explanation, I have a better visualization now.

[@AnthonyInSanDiego]

What is 'a' in the part where you explain the code?

[@coderbhaiya5328]

a is the starting point of string. Better call it -> swap(str[l], str[i])