Longest Substring Without Repeating Characters | Leetcode 3 | Sliding window

Time Complexity : O(n)
Space Complexity : O(1)
Problem Link : leetcode.com/p...
C++ Code Link : github.com/Ayu...
Please like, share and subscribe if you found the video useful. Feel free to ask in comments section if you have any doubts. :)
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#Leetcode
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Longest Substring Without Repeating Characters solution
Longest Substring Without Repeating Characters Leetcode
Longest Substring Without Repeating Characters C++
Longest Substring Without Repeating Characters Java
Longest Substring Without Repeating Characters Python
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[@jasper5016]

Thanks. Here is the Java code if someone needs it -
public int maxSubString(String s) {
int[] count = new int[256];
int l = 0;
int r = 0;
int ans = 0;
while (r < s.length()) {
char currChar = s.charAt(r);
count[currChar]++;
while (count[currChar] > 1) {
count[s.charAt(l)]--;
l++;
}
ans = Math.max(ans, r - l + 1);
r++;
}
return ans;
}

[@AyushiSharmaDSA]

thank you for sharing your code and helping others :)

[@azhargayawi]

after wasting approx 5 hours on you tube i found the genuine logic here, thank you mam. greaat....

[@AyushiSharmaDSA]

glad it was helpful :)

[@cs_soldier5292]

This can help someone :)
class Solution {
public:
int lengthOfLongestSubstring(string s) {
//creating a set to store the list
unordered_set ans;
int value=0;
int i=0,j=0;
while(i

[@coding619]

Good explanation but I guess the space complexity mentioned in the description should be O(k), where k are the unique characters and not O(1).

[@FootB_shorts1]

After wasting a lot of time i found A helpful video .
thanks❤❤

[@AyushiSharmaDSA]

welcome, glad u found it helpful :)

[@venkatvasamsetti8125]

I have already done this problem using hashmap.but without sliding window.thank you for this optimization of code

[@AyushiSharmaDSA]

Welcome Venkat, glad it was helpful :)

[@shinosukenohara.123]

can u explain your hashmap approach ?

[@user-er4hz8dg1g]

hi aushi, using two while loop may increase time complexity else we can use hash map for storing index of characters

[@ashjournal]

Waiting for Chennai vlog part 2 😍

[@AyushiSharmaDSA]

❤️❤️🙌🏻☺️

[@luckilygamer5462]

int lengthOfLongestSubstring(string s)
{
unordered_map umap;
int n = s.length();
int ans=0;
int start=0;
for (int i = 0; i < n; i++) {
if(umap.find(s[i])!=umap.end()){
// update the start index to the next character after the last occurrence
start = max(start, umap[s[i]] + 1);
}
umap[s[i]] = i;
ans=max(ans,i-start+1);
}
return ans;
}

[@priyankakataria7922]

Time complexity worst case will be O(n^2) right? Coz two while loops

[@ankitris5201]

crystal clear explanation mam 👍👍

[@AyushiSharmaDSA]

thank you :)

[@BADASSBLADE]

Solve Today's Leetcode Challenge(Erasure Problem,) by using this approach, thankyou keep up the good work

[@AyushiSharmaDSA]

Thanks ☺️

[@harshvardhan7762]

for java coders, there will be slight changes:-
public int lengthOfLongestSubstring(String s) {
int[] arr = new int[128];
int n = s.length();
int len = 0;
for(int i = 0, j = 0; j < n; j++){
int c = s.charAt(j);
arr[c]++;
if(arr[c] > 1){
while(arr[c] > 1){
arr[s.charAt(i)]--;
i++;
}
}
len = Math.max(len, j - i + 1);
}
return len;
}

[@SAHIL-jm2hv]

Thanks ma'am

[@AyushiSharmaDSA]

Most welcome 😊

[@abhishekprasad7568]

Di should i buy coding ninja dsa course or study from free resource . pls response

[@AyushiSharmaDSA]

The course is good and you can learn from free resources also, so it totally depends on you :)

[@pratiksuman007]

​ @AyushiSharmaDSA Your solution seems better then what available in general platform. What resource you have used to train yourself, could u make a video of it or if already there then link pls?

[@Srihan_kumar]

In gfg this code is not working

[@vamsiv5767]

This code gives wrong answer for aabccbb

[@jaikrishnapandey632]

Great explanation

[@AyushiSharmaDSA]

Thanks Jai :)

[@jagmohangautam1062]

it is giving runtime error for string containing space

[@abhisheknavhal1039]

The solution for the test case 'pwwkew' is not giving the correct answer.

[@samyakagarwal1777]

very well explained ...........100/100

[@AyushiSharmaDSA]

thank you :)

[@vinaykulkarni8863]

int lengthOfLongestSubstring(string s) {
unordered_mapmp;
int i=0,j=0,ans=0;
int n=s.length();
while(j1){
mp[s[i]]--;
i++;
}
ans=max(ans,j-i+1);
j++;
}
return ans;
}
};

[@aman_kumar0208]

Thanks di

[@AyushiSharmaDSA]

Welcome Aman 😊

[@bellanatrisha1201]

how is taking count[a] ?

[@kishorjanjal7454]

Thank for crisp solution 😌😌

[@AyushiSharmaDSA]

Welcome Kishor, glad it was helpful 😊

[@harishsonawane855]

Nice video

[@AyushiSharmaDSA]

Thanks Harish :)

[@akashonlinehere]

that code gives wrong ans in leetcode

[@softwareengineering101]

Nice explanation

[@arqamazmi3327]

Nice Explanation
Try this also.
Longest Repeating Character Replacement

[@AyushiSharmaDSA]

Thanks, sure 😊

[@ShaliniSingh-yo4rt]

Can we take char array of 128 size??

[@knixkcodes]

very well explained!

[@AyushiSharmaDSA]

Thank you , Glad it was helpful!

[@ashjournal]

👍👍

[@AyushiSharmaDSA]

😊😊

[@sumitpal9113]

Java code is not working in testcase "pwwkew". can any one help me.
public int lengthOfLongestSubstring(String s) {

int count[] = new int[256];

int maxLen = 0, i=0, j=0;

while(j < s.length()){
int index = s.charAt(j);
count[index]++;

while(count[index] > 1){
count[index]--;
i++;
}

maxLen = Math.max(maxLen,( j-i)+1);

j++;
}

return maxLen;
}

[@mohammedafreed9741]

In second while loop it's count[s.charAt(i)] not index. And why are you taking extra variable index

[@abhisheknavhal1039]

This solution is not working for pwwkew case

[@harshvardhan7762]

@@abhisheknavhal1039 in line 8, it will be ************** count[s.charAt(i)]--; ******************************will be there

[@bibs24]

Thanks a ton!

[@AyushiSharmaDSA]

Welcome :)

[@dhanrajlouvanshi7872]

i am waiting for this

[@AyushiSharmaDSA]

Thanks Dhanraj :)

[@deeptimayeemaharana2448]

You're best😁

[@AyushiSharmaDSA]

Thanks Deeptimayee 😊

[@amitsinha806]

👍👍👍👍👍👍👍👍👍👍👍👍👍👍

[@AyushiSharmaDSA]

Thanks Amit :)

[@UdayGarg]

thanks
]

[@AyushiSharmaDSA]

welcome :)

[@NikhilKumar-br4nj]

Didi if possible pls give java code also

[@user-uu2zk1tj6e]

You could've just took i and j. Why did you made it look difficult. We are beginners that's why we are here watching your videos. Please take care of it next time. Nice Explanation tho

[@CoDestination]

Hindi Java
czcams.com/video/hG2Fg6FlRA0/video.htmlsi=DlUeAE29pJsP5viX

[@umang1226]

please make in hindi we are more comfortable in it .

[@restless4263]

nice explanation

[@AyushiSharmaDSA]

thank you, glad you liked it :)

[@SuryajyotiDas]

thanks ma'am

[@AyushiSharmaDSA]

Welcome 🤗

[@KunalKashyap6]

thanku di

[@AyushiSharmaDSA]

Welcome Kunal :)