[LeetCode] 383. Ransom Note

Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false.

Each letter in the magazine string can only be used once in your ransom note.

Note:
You may assume that both strings contain only lowercase letters.

canConstruct("a", "b") -> falsecanConstruct("aa", "ab") -> falsecanConstruct("aa", "aab") -> true

class Solution {public:    bool canConstruct(string ransomNote, string magazine) {        vector<int> alphacnt(256, 0);        for (int i = 0; i < magazine.size(); i++)            alphacnt[magazine[i]]++;        for (int i = 0; i < ransomNote.size(); i++)            alphacnt[ransomNote[i]]--;        sort(alphacnt.begin(), alphacnt.end());        return alphacnt[0] >= 0;    }};