Leetcode 3 Longest Substring Without Repeating Characters

依旧水题一道，两头往后滑动，用数组映射出现的字符就行。

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.

class Solution {public:    int lengthOfLongestSubstring(string s)     {        int len=s.length();        int st=0,en=0,result=0;        int vis[1005];        memset(vis,0,sizeof(vis));        while(en<len)        {            int now=s[en];            while(st<en && vis[now])            {                vis[s[st]]=0;                st++;            }            vis[now]=1;            en++;            result=max(result,en-st);        }        return result;    }};