Leetcode #383 Ransom Note

Description

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

Explain

统计一个字符串各字母出现的次数，然后在另一个字符串里减即可，刚好python里有个计数的Counter

Code

class Solution(object):    def canConstruct(self, ransomNote, magazine):        """        :type ransomNote: str        :type magazine: str        :rtype: bool        """        import collections        return not collections.Counter(ransomNote) - collections.Counter(magazine)