LeetCode 3.无重复字符的最长子串

题目描述链接：https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/

解题思路：双指针

LeetCode C++参考代码如下：

class Solution {
public:
    unordered_set<char>record;
    int lengthOfLongestSubstring(string s) {
         int rk=-1;
         int res=0;
         for(int i=0;i<s.size();i++){
             if(i!=0){
                 record.erase(s[i-1]);
             }
             while(rk+1<s.size()&&!record.count(s[rk+1])){
                   rk++;
                   record.insert(s[rk]);
             }
             res=max(rk-i+1,res);
         }
         return res;
    }
};