前缀树Trie （python版本）（leetcode 208题）

class TrieNode(object):
    def __init__(self):
        self.path=0
        self.end=0
        self.map=[None for i in range(26)]
class Trie:
    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.root=TrieNode()

    def insert(self, word: str) -> None:
        """
        Inserts a word into the trie.
        """
        node=self.root
        if not word:
            return
        for i in word:
            index=ord(i)-ord('a')
            if node.map[index]==None:
                node.map[index]=TrieNode()
            node=node.map[index]
            node.path+=1
        node.end+=1

    def search(self, word: str) -> bool:
        """
        Returns if the word is in the trie.
        """
        if not word:
            return 0
        node=self.root
        for i in word:
            index=ord(i)-ord('a')
            if node.map[index]==None:
                return False
            node=node.map[index]
        return bool(node.end)

    def startsWith(self, prefix: str) -> bool:
        """
        Returns if there is any word in the trie that starts with the given prefix.
        """
        if not prefix:
            return
        node=self.root
        for i in prefix:
            index=ord(i)-ord('a')
            if node.map[index] == None:
                return False
            node = node.map[index]
        return bool(node.path)
    def dele(self,word):
        if self.search(word) != 0:
            node = self.root
            for i in word:
                index = ord(i)-ord('a')
                node.map[index].path -=1
                if node.map[index].path==0:
                    #本来原来就有一个  再删一个 就没了
                    #变成0 代表不需要此节点了
                    node.map[index] = None
                    return
                node = node.map[index]
            node.end-=1