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

class Solution(object):
    def canConstruct(self, ransomNote, magazine):
        """
        :type ransomNote: str
        :type magazine: str
        :rtype: bool
        """

        flag = True
        dica = {}
        for i in magazine:
            if not dica.has_key(i):
                dica[i]=1
            else:
                dica[i] += 1
        for i in ransomNote:
            if not dica.has_key(i):
                flag = False
                break
            else:
                dica[i] -= 1
                if dica[i]<0:
                    flag = False
                    break
        return flag