LeetCode – Refresh – Longest Substring Without Repeating Characters

 1 class Solution {
 2 public:
 3     int lengthOfLongestSubstring(string s) {
 4         int len = s.size(), result = 0;
 5         if (len < 2) return len;
 6         unordered_set<char> sets;
 7         for (int left = 0, right = 0; right < len; right++) {
 8             if (sets.find(s[right]) == sets.end()) {
 9                 result = max(result, right - left + 1);
10                 sets.insert(s[right]);
11             } else {
12                 sets.erase(s[left++]);
13                 right--;
14             }
15         }
16         return result;
17     }
18 };