Add and Search Word - Data structure design.md

Design a data structure that supports the following two operations:

void addWord(word)
bool search(word)
search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter.

Example:

addWord("bad")
addWord("dad")
addWord("mad")
search("pad") -> false
search("bad") -> true
search(".ad") -> true
search("b..") -> true

My code:

import collections
class WordDictionary(object):
    def __init__(self):
        self.len2words = collections.defaultdict(list) 

    def addWord(self, word):
        self.len2words[len(word)].append(word)

    def search(self, word):
        words = self.len2words[len(word)]
        for i, char in enumerate(word):
            words = [w for w in words if char in ('.', w[i])]
            if not words: return False
        return True

class WordDictionary1(object):

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.dict={}

    def addWord(self, word):
        """
        Adds a word into the data structure.
        :type word: str
        :rtype: void
        """
        self.dict[word]=1
        

    def search(self, word):
        """
        Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter.
        :type word: str
        :rtype: bool
        """
        if word in self.dict.keys():
            return True
        if '.' not in word:
            return False
        else:
            for item in self.dict.keys():
                if len(item)!=len(word):
                    continue
                flag=True
                for i in range(len(item)):
                    if word[i]=='.':
                        continue
                    if word[i]!=item[i]:
                        flag=False
                        break
                if flag:
                    return True
        return False
        


# Your WordDictionary object will be instantiated and called as such:
# obj = WordDictionary()
# obj.addWord(word)
# param_2 = obj.search(word)

Solution: https://leetcode.com/problems/add-and-search-word-data-structure-design/