# Leet code | Problem 3: Longest Substring Without Repeating Characters

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 = {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;
}
```