Sliding Window · Medium

Longest Substring Without Repeating Characters

O(N) · O(min(N, M))

Initialize Sliding Window

Input string: "abcabcbb". Set left pointer L=0, right pointer R=0, maxLen=0.

Array Elements & Pointers
L ↓
a
[0]
b
[1]
c
[2]
a
[3]
b
[4]
c
[5]
b
[6]
b
[7]
Live Variables & Invariants
s:abcabcbb
L:0
R:0
maxLen:0
windowSet:
Step 1 / 17
6%
Solution Code
1
function lengthOfLongestSubstring(s: string): number {
2
  const set = new Set<string>();
3
  let l = 0, max = 0;
4
  for (let r = 0; r < s.length; r++) {
5
    while (set.has(s[r])) { set.delete(s[l]); l++; }
6
    set.add(s[r]);
7
    max = Math.max(max, r - l + 1);
8
  }
9
  return max;
10
}
LeetCode IDE Console

Test Cases

6 cases from Blind 75 & NeetCode 150

Ask for a hint whenever you get stuck.