211. Add and Search Word - Data structure design

class TrieNode {
    boolean isWord;
    TrieNode[] children;
    
    public TrieNode() {
        isWord = false;
        children = new TrieNode[26];
    }
}

class WordDictionary {
    
    TrieNode root;

    /** Initialize your data structure here. */
    public WordDictionary() {
        root = new TrieNode();
    }
    
    /** Adds a word into the data structure. */
    public void addWord(String word) {
        TrieNode cur = root;
        for (int i = 0; i < word.length(); i++) {
            int c = word.charAt(i) - 'a';
            if (cur.children[c] == null) {
                cur.children[c] = new TrieNode();
            }
            cur = cur.children[c];
        }
        cur.isWord = true;
    }
    
    /** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
    public boolean search(String word) {
        return search(word.toCharArray(), 0, root);
    }
    
    private boolean search(char[] cArray, int index, TrieNode node) {
        if (index == cArray.length) {
            return node.isWord;
        }
        if (cArray[index] == '.') {
            for (int i = 0; i < node.children.length; i++) {
                if (node.children[i] != null) {
                    if (search(cArray, index + 1, node.children[i])) {
                        return true;
                    }
                }
            }
        } else {
            return node.children[cArray[index] - 'a'] != null
                && search(cArray, index + 1, node.children[cArray[index] - 'a']);
        }
        return false;
    }
}

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