struct Node{
    bool exist;
    Node * nodes[26]={0};
    Node(const bool & e=false):exist(e){}
    Node * & get_node(const char & a)
    {
        return nodes[a-'a'];
    }
    const Node * get_node(const char & a) const
    {
        return nodes[a-'a'];
    }
};
class WordDictionary {
public:
    Node root;
    void addWord(string word) {
        Node * tmp = &root;
        for(const auto & c:word)
        {
            if(!tmp->get_node(c))
                 tmp->get_node(c) = new Node();
            tmp= tmp->get_node(c);
        }
        tmp->exist = true;
    }
    bool srch(const Node * now,const char *ptr)
    {
        if(now == NULL || *ptr == '\0')
            return now && now->exist;
        if(*ptr!='.')
            return srch(now->get_node(*ptr),ptr+1);
        else
             for(char c = 'a'; c <='z'; c++)
                if(srch(now->get_node(c),ptr+1))
                    return true;
        return false;
    }


    // Returns if the word is in the data structure. A word could
    // contain the dot character '.' to represent any one letter.
    bool search(string word) {
         return srch(&root,word.c_str());
    }
};

// Your WordDictionary object will be instantiated and called as such:
// WordDictionary wordDictionary;
// wordDictionary.addWord("word");
// wordDictionary.search("pattern");