LeetCode: 383 Ransom Note(easy)

题目：

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") -> false
 canConstruct("aa", "ab") -> false
 canConstruct("aa", "aab") -> true

代码:

 class Solution {
 public:
     bool canConstruct(string ransomNote, string magazine) {
         if (ransomNote == "")
             return true;
         for (auto c : ransomNote){
             int position = magazine.find_first_of(c);
             if (position != magazine.npos)
                 magazine.erase(position, );
             else
                 return false;
         }
        return true;
     }
 };

别人的：

 class Solution {
 public:
     bool canConstruct(string ransomNote, string magazine) {
         int mp[] = {};
         for(auto c : magazine) {
             mp[c - 'a']++;
         }
         for(auto r : ransomNote) {
             mp[r - 'a']--;
             if(mp[r - 'a'] < ) return false;
         }
         return true;
     }
 };