383.cpp

class Solution {
public:
    bool canConstruct(string ransomNote, string magazine) {
        unordered_map<char, int> res(26);
        for(int i = 0; i < magazine.size(); i++)
            ++res[magazine[i]];
        for(int j = 0; j < ransomNote.size(); j++)
            if (--res[ransomNote[j]] < 0) return false;
        return true;
    }
};