leetcode211

class TrieNode:
    def __init__(self):
        self.words = 0
        self.edges = [None] * 26


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

    def addWord(self, word: str) -> None:
        self.insertHelper(self.root,word,0)

    def search(self, word: str) -> bool:
        return self.searchHelper(self.root,word,0) != 0

    def insertHelper(self,node,word,pos):
        if pos == len(word):
            node.words += 1
        else:
            char_code = ord(word[pos]) - 97
            if node.edges[char_code] == None:
                node.edges[char_code] = TrieNode()
            self.insertHelper(node.edges[char_code],word,pos+1)


    def searchHelper(self,node,word,pos):
        if pos == len(word):
            return node.words
        else:
            if word[pos] == '.':#任意字符的判断
                for i in range(26):
                    if node.edges[i] != None:
                        res = self.searchHelper(node.edges[i],word,pos+1)
                        if res != 0:
                            return res
                return 0
            else:#具体字母的判断
                char_code = ord(word[pos]) - 97
                if node.edges[char_code] == None:
                    return 0
                else:
                    return self.searchHelper(node.edges[char_code],word,pos+1)

算法思路：前序树Trie。

根据 leetcode208 Implement Trie (Prefix Tree)，改造出来的。