[leetcode]438. Find All Anagrams in a String

Analysis

everyday is the first day of your rest life—— [间歇性迷茫+1~]

Given a string s and a non-empty string p, find all the start indices of p’s anagrams in s.
Strings consists of lowercase English letters only and the length of both strings s and p will not be larger than 20,100.
The order of output does not matter.
看s中是否包含p，输出子串在s中的起始位置。自己暴力做了一个一直超时，然后看了题解，用的滑动窗口，这题需要二刷！！！

Implement

class Solution {
public:
    vector<int> findAnagrams(string s, string p) {
        vector<int> res;
        vector<int> cnt(128, 0);
        int lens = s.length();
        int lenp = p.length();
        for(int i=0; i<lenp; i++)
            cnt[p[i]]++;
        int left = 0;
        int right = 0;
        int len = lenp;
        while(right < lens){
            if(cnt[s[right++]]-- >= 1){
                len--;
            }
            if(len == 0)
                res.push_back(left);
            if(right-left == lenp && cnt[s[left++]]++ >= 0){
                len++;
            }
        }
        return res;
    }
};