LeetCode *567. 字符串的排列(滑动窗口)(双指针)

class Solution {
public:
    bool checkInclusion(string s1, string s2) {
        map<char, int> mp0;
        map<char, int> mp1;
        if (s2.size() == 0) {
            return false;
        }
        if (s1.size() == 0) {
            return true;
        }
        int count = 0, left = 0, right = s1.size() - 1;
        for (int i = 0; i < s1.size(); i++) {
            mp0[s1[i]]++;
        }
        for (int i = left; i <= right && i < s2.size(); i++) {
            mp1[s2[i]]++;
        }
        while (right < s2.size() - 1) {
            if (mp0 == mp1) return true;
            mp1[s2[left]]--;
            if (mp1[s2[left]] == 0) { 
                for (auto it = mp1.begin(); it != mp1.end(); it++) {
                    if (it->first == s2[left]) {
                        mp1.erase(it);
                        break;
                    }
                }
            }
            if (right < s2.size() - 1) right++;
            left++;
            mp1[s2[right]]++;
        }
        if (mp0 == mp1) return true;
        return false;
    }
};