leetcode 438. 找到字符串中所有字母异位词

解题思路

思路同经典的76.最小覆盖子串，https://leetcode-cn.com/problems/minimum-window-substring/solution/c-hua-dong-chuang-kou-z-by-zrita/

代码

class Solution {
public:
    vector<int> findAnagrams(string s, string p) {
        vector<int> res;
        int m[128] = {0};
        int left = 0, right = 0, need = 0;
        for(char c : p)
            ++m[c];
        while(right < s.size())
        {
            if(m[s[right]] > 0)     ++need;
            --m[s[right]];
            ++right;
            while(need == p.size())
            {
                if(right - left == p.size())   res.push_back(left);      //通过长度判断异位词，加入res中
                if(m[s[left]] == 0)     --need;
                ++m[s[left]];
                ++left;
            }
        }
        return res;
    }
};