[LeetCode] 567. Permutation in String c++

• 문제

Given two strings s1 and s2, return true if s2 contains a permutation of s1, or false otherwise.

In other words, return true if one of s1's permutations is the substring of s2.

 

Input: s1 = "ab", s2 = "eidbaooo"
Output: true
Explanation: s2 contains one permutation of s1 ("ba").

 

• 문제 해결

class Solution {
public:
    bool checkInclusion(string s1, string s2) {
        if( s1.size() > s2.size())
            return false;
        
        vector<int> vec(26, 0);
        for(const auto& it : s1){
            vec[it-'a']++;
        }
        
        vector<int> vec2(26, 0);
        int l = 0, r = 0;
        while( r < s2.size()){
            vec2[s2[r]-'a']++;
            if( r - l + 1 == s1.size() && vec == vec2){
                return true;
            }
            if( r - l + 1 < s1.size()){
                r++;
            }
            else{
                vec2[s2[l] - 'a']--;
                l++;
                r++;
            }
        }
        return false;
    }
};