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;
};