Given a string, find the length of the longest substring without repeating characters. For example, the longest substrings without repeating characters for “ABDEFGABEF” are “BDEFGA” and “DEFGAB”, with length 6.

Example:

Input:
2
geeksforgeeks
qwertqwer

Output:
7
5

Given a string, find the length of the longest substring without repeating characters. 

#include <bits/stdc++.h>

using namespace std;

int main() {
    //code
    int t;
    cin >> t;
    while (t--) {
        string s;
        cin >> s;
        int a[26];
        int i = 0, j = 0, l = 0;
        memset(a, 0, sizeof(a));

        while (j < s.size()) {

            while (i < s.size()) {

                a[s[i] - 'a'] += 1;
                if (a[s[i] - 'a'] >= 2) {
                    l = max(l, i - j);
                    memset(a, 0, sizeof(a));
                    break;
                }
                ++i;

            }
            l = max(l, i - j);
            ++j;
            i = j;
        }
        cout << l << endl;

    }
    return 0;
}