题目描述

blablabla

样例

blablabla

算法1(滑动窗口)

class Solution {
public:
    int longestSubstringWithoutDuplication(string s) {
        unordered_map<char,int> windows;
        int res=0;
        int len=s.size();
        int left=0,right=0;
        while (right<len) {
            char c=s[right];
            windows[c]++;
            right++;
            while (windows[c]>1) {
                char d=s[left];
                windows[d]--;
                left++;
            }
            res=max(res,right-left);
        }
        return res;
    }
};