Three Longest Substring Without Repeating Character Leetcode Solution

/**
 * @param {string} s
 * @return {number}
 */
const lengthOfLongestSubstring = function (s) {
  if (s.length < 2) return s.length
  const hash = {}
  let max = 0
  for (let i = 0, j = -1, len = s.length; i < len; i++) {
    const cur = s[i]
    if (hash[cur] != null) j = Math.max(j, hash[cur])

    hash[cur] = i
    max = Math.max(max, i - j)
  }

  return max
}

// another

/**
 * @param {string} s
 * @return {number}
 */
const lengthOfLongestSubstring = function (s) {
  // var p=0, q=0; //p: start of the sub, q: end of the queue

  //hashmap in js????? Array.indexOf
  const sub = []
  let max = 0

  for (let i = 0; i < s.length; i++) {
    let index = sub.indexOf(s.charAt(i))
    if (index == -1) {
      sub.push(s.charAt(i))
      // q++;
    } else {
      //find repeat, get index of repeat el, remve all el before that index
      sub = sub.slice(index + 1, sub.length)
      sub.push(s.charAt(i))
    }
    max = Math.max(max, sub.length)
  }
  return max
}