Unique Word Abbreviation

这里的unique不光说的是这个缩写在字典里面没有，如果字典里面有这个缩写但是只有这一个词也是可以的

class ValidWordAbbr(object):

    def __init__(self, dictionary):
        """
        :type dictionary: List[str]
        """
        self.store = {}
        for word in dictionary:
            abbr = word
            length = len(word)
            if length > 2:
                abbr = word[0] + `length - 2` + word[-1]
            self.store.setdefault(abbr, set([]))
            self.store[abbr].add(word)

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

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