【35】3. Longest Substring Without Repeating Characters

 1 class Solution {
 2 public:
 3     int lengthOfLongestSubstring(string s) {
 4         int m[256] = {-1};
 5         int left = 0;
 6         //int right = 0;//不需要用到right，往右走的时候直接用i替代即可
 7         int res = 0;
 8         for(int i = 0; i < s.size(); i++){
 9             if(m[s[i]] == 0 || m[s[i]] < left){
10                 res = max(res, i - left + 1);
11             }else{
12                 left = m[s[i]];//更新左边界
13             }
14             m[s[i]] = i + 1;//这样赋值，记录的是下次的最左边界可以到哪里
15         }
16         return res;
17     }
18 };