[刷题] LeetCode 3 Longest Substring Without Repeating Character

 1 class Solution{
 2 public:
 3     int lenthOfLongestSubstring(string s){
 4         int freq[256] = {0};
 5         int l = 0, r = -1;
 6         int res = 0;
 7         
 8         while(l < s.size()){
 9             if( r + 1 < s.size() && freq[s[r+1]] == 0)
10                 freq[s[++r]] ++ ;
11             else
12                 freq[s[l++]] -- ;
13             res = max(res, r-l+1); 
14         }
15         return res;
16     }
17 };