1// Longest Substring Without Repeating Characters
2// Time: O(n)  Space: O(min(m,n))
3
4export function lengthOfLongestSubstring(s: string): number {
5  const seen = new Map<string, number>();
6  let left = 0, best = 0;
7
8  for (let right = 0; right < s.length; right++) {
9    const c = s[right];
10    if (seen.has(c) && seen.get(c)! >= left) {
11      left = seen.get(c)! + 1;
12    }
13    seen.set(c, right);
14    best = Math.max(best, right - left + 1);
15  }
16  return best;
17}