3. Longest Substring Without Repeating Characters

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) {
    let stack = [], m = s.split(''), maxCount = 0, maxArr = [], ticker = 0;
    for (let i = 0; i < m.length; i++) {
        let cur = m[i], q = stack.indexOf(cur);
        if (q == -1) {
            stack.push(cur);
            ticker = stack.length;
            if (ticker > maxCount) {
                maxCount = ticker;
                maxArr = [...stack];
            }
        } else {
            stack.splice(0, q + 1);
            stack.push(cur);
            ticker = stack.length;
        }
    }
    return maxCount;
}