3. Longest Substring Without Repeating Characters.c

int lengthOfLongestSubstring(char *s)
{
    int len = strlen(s);
    char map[256] = {0};

    int l = 0;
    int r = 0;
    int max = 0;

    while (r < len)
    {
        map[s[r]]++;

        while (map[s[r]] > 1)
        {
            map[s[l]]--;
            l++;
        }

        if (max < (r - l + 1))
            max = r - l + 1;
        r++;
    }

    return max;
}