class Solution {
public:
bool canConstruct(string ransomNote, string magazine) {
int hash[26] = {0};
for (char ch:magazine) hash[ch-'a']++;
for (char ch:ransomNote){
hash[ch-'a']--;
if (hash[ch-'a']<0) return false;
}
// 也可拆开写
// for (char ch:ransomNote) hash[ch-'a']--;
// for (int i:hash) if(i<0) return false;
return true;
}
};