NOTE: This problem is generated by LeetCode. TakeTheNotes has given only solution for educational purpose.


Problem Name: Longest Substring Without Repeating Characters

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

Example 1:

Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.

Example 2:

Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.

Constraints:

  • 0 <= s.length <= 5 * 104
  • s consists of English letters, digits, symbols and spaces.

Solution:

int lengthOfLongestSubstring(char * s){

    int len = strlen(s);
    if(len <= 1)
    {
        return len;
    }

    int max = 1;
    int currentLen;

    for(int i = 0; i < len; i++)
    {
        currentLen = 1;

        bool seen[256] = {0, };

        for(int j = i+1; j < len; j++)
        {
            if(s[i] != s[j])
            {
                if(seen[s[j]] == true)
                {
                    //This character was already seen before
                    break;
                }

                currentLen++;
                seen[s[j]] = true;
            }
            else
            {
                break;
            }
        }

        max = (max > currentLen) ? max : currentLen;
    }
    
    return max;
}