實現字典數（Trie）

class Trie(object):

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.root={}
        self.end_of_word='#'

    def insert(self, word):
        """
        Inserts a word into the trie.
        :type word: str
        :rtype: None
        """
        node=self.root
        for char in word:
            node=node.setdefault(char,{})
        node[self.end_of_word]=self.end_of_word

    def search(self, word):
        """
        Returns if the word is in the trie.
        :type word: str
        :rtype: bool
        """
        node=self.root
        for char in word:
            if char not in node:
                return False
            else:
                node=node[char]
    
        return self.end_of_word in node 
        

    def startsWith(self, prefix):
        """
        Returns if there is any word in the trie that starts with the given prefix.
        :type prefix: str
        :rtype: bool
        """
        node=self.root
        for char in prefix:
            if char not in node:
                return False
            else:
                node=node[char]
        return True
        


# Your Trie object will be instantiated and called as such:
# obj = Trie()
# obj.insert(word)
# param_2 = obj.search(word)
# param_3 = obj.startsWith(prefix)