[LeetCode]383. Ransom Note

[LeetCode]383. Ransom Note

题目描述

思路

map保存，然后检查时候递减，若小于0则FALSE
发现用vector速度更快

代码

#include <iostream>
#include <string>
#include <unordered_map>
using namespace std;

class Solution {
public:
    bool canConstruct(string ransomNote, string magazine) {
        /*
        unordered_map<char, int> um;
        for (char p : magazine)
            ++um[p];
        for (char p : ransomNote)
            if (--um[p] < 0)
                return false;
        return true;
        */
        vector<int> ch(26, 0);
        for (char p : magazine)
            ++ch[p - 'a'];
        for (char p : ransomNote)
            if (--ch[p - 'a'] < 0)
                return false;
        return true;
    }
};

int main() {
    Solution s;
    cout << s.canConstruct("aa", "aab") << endl;
    system("pause");
}