# Longest Substring Without Repeating Characters LeetCode Solution Best & Easiest In this post, we will solve the Longest Substring Without Repeating Characters LeetCode Solution.

Problem Statement:

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.```

## Longest Substring Without Repeating Characters LeetCode Solution

### Problem solution in JavaScript programming:

```function lengthOfLongestSubstring(s) {
let maxLength = 0, start = 0, end = 0;
const charIndexMap = {};

while (end < s.length) {
const char = s[end];
if (charIndexMap[char] >= start) {
start = charIndexMap[char] + 1;
}
charIndexMap[char] = end;
maxLength = Math.max(maxLength, end - start + 1);
end++;
}

return maxLength;
}
```

### Problem solution in Python programming:

```def lengthOfLongestSubstring(self, s):
max_length = 0
start = 0
char_index_map = {}

for end in range(len(s)):
char = s[end]
if char in char_index_map and char_index_map[char] >= start:
start = char_index_map[char] + 1
char_index_map[char] = end
max_length = max(max_length, end - start + 1)

return max_length
```

### Problem solution in C++ programming:

```int lengthOfLongestSubstring(std::string s) {
int maxLength = 0;
int start = 0;
std::unordered_map<char, int> charIndexMap;

for (int end = 0; end < s.length(); end++) {
char c = s[end];
if (charIndexMap.count(c) && charIndexMap[c] >= start) {
start = charIndexMap[c] + 1;
}
charIndexMap[c] = end;
maxLength = std::max(maxLength, end - start + 1);
}

return maxLength;
}
```