class Trie {    private TrieNode root;    class TrieNode {        TrieNode[] children = new TrieNode[26];        boolean isWord;    }    /** Initialize your data structure here. */    public Trie() {        root = new TrieNode();    }        /** Inserts a word into the trie. */    public void insert(String word) {        TrieNode runner = root;        for (char c : word.toCharArray()) {            if (runner.children[(int)(c - 'a')] == null) {                runner.children[(int)(c - 'a')] = new TrieNode();            }            runner = runner.children[(int)(c - 'a')];        }        runner.isWord = true;    }        /** Returns if the word is in the trie. */    public boolean search(String word) {        TrieNode runner = root;        for (char c : word.toCharArray()) {            if (runner.children[(int)(c - 'a')] == null) {                return false;            }            runner = runner.children[(int)(c - 'a')];        }        return runner.isWord;    }        /** Returns if there is any word in the trie that starts with the given prefix. */    public boolean startsWith(String prefix) {        TrieNode runner = root;        for (char c : prefix.toCharArray()) {            if (runner.children[(int)(c - 'a')] == null) {                return false;            }            runner = runner.children[(int)(c - 'a')];        }                return isWords(runner);    }        private boolean isWords(TrieNode node) {        if (node == null) {            return false;        }                if (node.isWord) {            return true;        }                for (TrieNode child : node.children) {            if (isWords(child)) {                return true;            }        }        return 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); */