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

Example 1:

Input: "abcabcbb"

Output: 3

Explanation: The answer is "abc", with the length of 3.

Example 2:

Input: "bbbbb"

Output: 1

Explanation: The answer is "b", with the length of 1.

Example 3:

Input: "pwwkew"

Output: 3

Explanation: The answer is "wke", with the length of 3.

Note that the answer must be a substring, "pwke" is a subsequence and not a substring.

```
/**
* @param {string} s
* @return {number}
*/
var lengthOfLongestSubstring = function(s) {
var max = 0;
var a = [];
for (var i = 0; i < s.length; i ++){
// If element exists, remove any other elements before it,
// and itself
if(a.includes(s[i])){
a.splice(0, a.indexOf(s[i]) + 1);
}
// Append new element
a.push(s[i]);
// Update result
if(max < a.length){
max = a.length;
}
}
return max;
};
```