面试题48. 最长不含重复字符的子字符串

 1 class Solution {
 2 public:
 3     int lengthOfLongestSubstring(string s) 
 4     {
 5         map<char, int> m;
 6         int ret = 0, l = 0, r = 0;
 7         while (r < s.size()) 
 8         {
 9             if (m.find(s[r]) != m.end()) 
10             {
11                 l = max(l, m[s[r]] + 1);
12             }
13             m[s[r]] = r;
14             r++;
15             ret = max(r - l, ret);
16         }
17         return ret;
18     }
19 };