384. Longest Substring Without Repeating Characters

class Solution { public: /** * @param s: a string * @return: an integer */ int lengthOfLongestSubstring(string &s) { // write your code here const int size = s.size(); if(size <= 1){ return size; } int left = -1; int res = 1; unordered_map<int, int> mp; for(int i = 0; i < size; i++){ if(mp.count(s[i])){ left = max(left, mp[s[i]]); } res = max(res, i - left); mp[s[i]] = i; } return res; } };