Unique Word Abbreviation

简单的模拟题，记住题目要求里奇怪的判断条件就好

class ValidWordAbbr(object):

    def __init__(self, dictionary):
        """
        :type dictionary: List[str]
        """
        self.store = collections.defaultdict(list)
        for word in dictionary:
            if len(word) <= 2:
                self.store[word].append(word)
                continue
            self.store[word[0] + `len(word) - 2` + word[-1]].append(word)

    def isUnique(self, word):
        """
        :type word: str
        :rtype: bool
        """
        if len(word) <= 2:
            return True
        abbre = word[0] + `len(word) - 2` + word[-1]
        if abbre not in self.store:
            return True
        elif len(self.store[abbre]) == 1 and self.store[abbre][0] == word:
            return True
        return False


# Your ValidWordAbbr object will be instantiated and called as such:
# obj = ValidWordAbbr(dictionary)
# param_1 = obj.isUnique(word)

这里如果用set会更加快