Thiết kế Thêm và tìm kiếm từ

class TrieNode:
    def __init__(self):
        self.children = {}
        self.end = False
class WordDictionaryOpt:
    def __init__(self):
        self.root = TrieNode()
    def addWord(self, word):
        curr = self.root
        for c in word:
            if c not in curr.children: curr.children[c] = TrieNode()
            curr = curr.children[c]
        curr.end = True
    def search(self, word):
        def dfs(j, root):
            curr = root
            for i in range(j, len(word)):
                c = word[i]
                if c == ".":
                    for child in curr.children.values():
                        if dfs(i + 1, child): return True
                    return False
                else:
                    if c not in curr.children: return False
                    curr = curr.children[c]
            return curr.end
        return dfs(0, self.root)

class WordDictionaryBrute:
    def __init__(self):
        self.words = set()
    def addWord(self, word):
        self.words.add(word)
    def search(self, word):
        if '.' not in word: return word in self.words
        for w in self.words:
            if len(w) == len(word):
                match = True
                for i in range(len(word)):
                    if word[i] != '.' and word[i] != w[i]:
                        match = False; break
                if match: return True
        return False