211. Add and Search Word - Data structure design

class TrieNode {
public:
    TrieNode* children[26];
    bool word;
    TrieNode() {
        word = false;
        memset(children, NULL, sizeof(children));
    }
};

class WordDictionary {
public:
    /** Initialize your data structure here. */
    WordDictionary() {
        root = new TrieNode();
    }
    
    /** Adds a word into the data structure. */
    void addWord(string word) {
        TrieNode* node = root;
        for (char c : word) {
            if (!node->children[c-'a'])
                node->children[c-'a'] = new TrieNode();
            node = node->children[c-'a'];
        }
        node->word = true;
    }
    
    /** 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 query(word.c_str(), root);
    }
private:
    TrieNode* root;
    bool query(const char* word, TrieNode* node) {
        for (int i = 0; word[i] && node; ++i) {
            if (word[i] != '.') {
                node = node->children[word[i] - 'a'];
            } else {
                TrieNode* temp = node;
                for (int j = 0; j < 26; ++j) {
                    node = temp->children[j];
                    if (query(word+i+1, node)) {
                        return true;
                    }
                }
            }
        }
        return node && node->word;
    }
};

/**
 * Your WordDictionary object will be instantiated and called as such:
 * WordDictionary obj = new WordDictionary();
 * obj.addWord(word);
 * bool param_2 = obj.search(word);
 */