leetcode211. 添加与搜索单词 - 数据结构设计

节点法前缀树加DFS

class TrieNode(object):
    def __init__(self):
        self.children = [None]*26
        self.flag = False
class WordDictionary(object):
    def __init__(self):
        self.root = TrieNode()
    def addWord(self, word):
        """
        :type word: str
        :rtype: None
        """
        node = self.root
        for i in word:
            ch = ord(i)-ord("a")
            if not node.children[ch]:
                node.children[ch] = TrieNode()
            node = node.children[ch]
        node.flag = True
                 
    def search(self, word):
        """
        :type word: str
        :rtype: bool
        """
        def dfs(index,node):
            if len(word) == index:
                return node.flag
            ch = word[index]
            if ch != ".":
                child = node.children[ord(ch) - ord('a')]
                if child is not None and dfs(index + 1, child):
                    return True
            else:
                for child in node.children:
                    if child is not None and dfs(index+1,child):
                        return True
            return False
        return dfs(0,self.root)
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字典法前缀树加DFS

class TrieNode(object):
    def __init__(self):
        self.children = {}
        self.flag = False
class WordDictionary(object):
    def __init__(self):
        self.root = TrieNode()
    def addWord(self, word):
        node = self.root
        for c in word:
            if c not in node.children:
                node.children[c] = TrieNode()
            node = node.children[c]
        node.flag = True
    def search(self, word):
        def dfs(index,node):
            if not node:
                return False
            if index == len(word):
                return node.flag
            ch = word[index]
            if ch != '.':
                if ch not in node.children:
                    return False
                node = node.children[ch]
                return dfs(index+1,node)
            else:
                for child in node.children.values():
                    if dfs(index+1,child):
                        return True
            return False
        return dfs(0,self.root)
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