Leetcode 3. Longest Substring Without Repeating Characters (滑动窗口解法)

话说我有一个小习惯，我会去看一下 Debugu code in playground, 我觉得它的题目的输入输出的代码都写的特别的棒。

Given a string, find the length of the longest substring without repeating characters.

Examples:

Given "abcabcbb", the answer is "abc", which the length is 3.

Given "bbbbb", the answer is "b", with the length of 1.

Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequence and not a substring.

解析：不要去看别人的二手资料，去看官方解析！！！！：https://leetcode.com/problems/longest-substring-without-repeating-characters/solution/

 我用的是C++的 set容器， insert ( s [ j ] ) 返回的类型是 pairs (set<char>::iterator, bool )类型的，判断第二个是不是true就好了， 当然大部分人用的都是java -  -。 这个是我的，也 po 在了后面的讨论区。

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        set<char> myset;
        int ans = 0, i = 0, j = 0;
        for(; i < s.length(); ++i){
            while(myset.insert(s[j]).second && j < s.length()){
                j++; 
                ans = max(ans, j-i);
            }
            myset.erase(s[i]);
        }
        return ans;
    }
};