LEETCODE 208. 实现 Trie (前缀树)

class Trie(object):

    def __init__(self):
        self.root=TrieNode()

    def insert(self, word):
        """
        :type word: str
        :rtype: None
        """
        node=self.root
        for i in word:
            index=ord(i)-ord('a')
            if node.children[index] is None:
                node.children[index]=TrieNode()
            node=node.children[index]
        node.is_world=True
        

    def search(self, word):
        """
        :type word: str
        :rtype: bool
        """
        node=self.root
        for i in word:
            index=ord(i)-ord('a')
            if node.children[index] is None:
                return False
            node=node.children[index]
        return node.is_world

    def startsWith(self, prefix):
        """
        :type prefix: str
        :rtype: bool
        """
        node=self.root
        for i in prefix:
            index=ord(i)-ord('a')
            if node.children[index] is None:
                return False
            node=node.children[index]
        return True
class TrieNode:
    def __init__(self):
        self.children=[None]*26
        self.is_world=False



# 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)