Pls tell the error in code.. the code is to find longest substring without repeating character

#1

int longestSubstr(string S) {
if(S.size() <= 1){
return S.size();
}

int sl = S.size();
int sf[256] = {0};
int start = 0;

int max_length = INT_MIN;
int i;
for(i=0;i<sl;i++){
    char ch = S[i];
    if(sf[ch] == 0){
        sf[ch]++;
    }
    else{
        int curr_len = i - start;
        max_length = max(max_length, curr_len);
        while(S[start] != ch){
            sf[S[start]]--;
            start++;
        }
        start++;
        sf[S[start]]++;
    }
}
return max(max_length, i-start);

}

#2

hey @Vaibhav277 :smile:,
i would request you to save your code at ide.codingblocks.com and share your entire code here .
Thank you

#3
#4

Hey @Vaibhav277 :smile:,
you have attached your doubt with question Minimum Window Substring (Sliding Window) :star:, but you are asking doubt of question Length Of Longest Substring Without Repeat. I would request you to post your doubt again with respective problem you have to ask :smile:. Thank you.

#5

hmm… actually this problem is not in course … i was solving it somewhere and test cases were not passing… so i posted it here… my output is coming correct… can u pls check if there is some error or not

#6

You can use this one maybe it will help you

int lengthOfLongestSubstring(string s) {
if(s.size() <= 1)
return s.size();
string str;
int max_size = INT_MIN;
for(auto i = s.begin(); i != s.end(); i++)
{
if (max_size == INT_MIN)
{
str.push_back(*i);
max_size = str.length();
continue;
}
if(str.find(*i) == string::npos)
{
str.push_back(*i);
max_size = max_size < str.length()?str.length():max_size;
}
else
{
str.erase(0,str.find(*i)+1);
str.push_back(*i);
}
}
return max_size;
}

#7

actually i was trying to use the concept of sliding window in that… so can u suggest changes in my code only

#8

for sliding window approach you can use this

//Sliding window
        int n=s.size();
        int i(0), j(0);
        if(n==0) return 0;
        vector<int>cnt(326, 0);
        cnt[s[0]]++;
        int maxLen=1;
        while(j!=n-1){
            if(cnt[s[j+1]]!=1){
                cnt[s[j+1]]++;
                j++;
                maxLen=max(maxLen, j-i+1);
            }else{
                cnt[s[i]]--;
                i++;
            }
        }
        return maxLen;
#9

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