383. 赎金信

class Solution 
{
public:
    bool canConstruct(string ransomNote, string magazine) 
    {
        unordered_map<char,int> hash_r,hash_m;
        for(auto a : magazine) hash_m[a] ++;
        for(auto a : ransomNote) hash_r[a] ++;
        for(auto a : hash_r)
        {
            if(a.second > hash_m[a.first]) return false;
        }
        return true;
    }
};