Implement a trie withinsert,search, andstartsWithmethods.

Note:
You may assume that all inputs are consist of lowercase lettersa-z.

class Trie {
    TrieNode root;
    /** Initialize your data structure here. */
    public Trie() {
       root = new TrieNode(); 
    }

    /** Inserts a word into the trie. */
    public void insert(String word) {
        TrieNode node = root;
        for (int i = 0; i < word.length(); i++) {
            int pos = word.charAt(i) - 'a';
            if (node.children[pos] == null) {
                node.children[pos] = new TrieNode();
            }
            node = node.children[pos];
        }
        node.isWord = true;
    }

    /** Returns if the word is in the trie. */
    public boolean search(String word) {
        TrieNode node = root;
        for (int i = 0; i < word.length(); i++) {
            int pos = word.charAt(i) - 'a';
            if (node.children[pos] == null) {
                return false;
            }
            node = node.children[pos];
        }
        return node.isWord;
    }

    /** Returns if there is any word in the trie that starts with the given prefix. */
    public boolean startsWith(String prefix) {
        TrieNode node = root;
        for (int i = 0; i < prefix.length(); i++) {
            int pos = prefix.charAt(i) - 'a';
            if (node.children[pos] == null) {
                return false;
            }
            node = node.children[pos];
        }
        return true;
    }
    private class TrieNode {
        TrieNode[] children;
        boolean isWord;
        private TrieNode(){
            children = new TrieNode[26];
            isWord = false;
        }

    }
}

/**
 * Your Trie object will be instantiated and called as such:
 * Trie obj = new Trie();
 * obj.insert(word);
 * boolean param_2 = obj.search(word);
 * boolean param_3 = obj.startsWith(prefix);
 */