LeetCode: Longest Substring Without Repeating Characters Solution

Approach

Use Set() for efficient repeating characters check

Implementation

1var lengthOfLongestSubstring = function (s) {
2  const set = new Set()
3  let res = 0
4
5  for (let lo = (hi = 0); hi < s.length; ) {
6    if (set.has(s[hi])) {
7      set.delete(s[lo])
8      lo++
9    } else {
10      set.add(s[hi])
11      hi++
12      res = Math.max(res, set.size)
13    }
14  }
15
16  return res
17}