Implement a trie with insert, search, and startsWith methods.

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

一刷
trie

public class Trie {
    
    public class TrieNode{
        public TrieNode[] children = new TrieNode[26];
        public boolean endOfWord = false;
    }
    
    private TrieNode root;

    /** Initialize your data structure here. */
    public Trie() {
        root = new TrieNode();
    }
    
    /** Inserts a word into the trie. */
    public void insert(String word) {
        TrieNode cur = root;
        for(int i=0; i<word.length(); i++){
            char ch = word.charAt(i);
            if(cur.children[ch - 'a'] == null){
                cur.children[ch - 'a'] = new TrieNode();
            }
            cur = cur.children[ch - 'a'];
        }
        cur.endOfWord = true;
    }
    
    /** Returns if the word is in the trie. */
    public boolean search(String word) {
        TrieNode cur = root;
        for(int i=0; i<word.length(); i++){
            char ch = word.charAt(i);
            if(cur.children[ch - 'a'] == null) return false;
            cur = cur.children[ch - 'a'];
        }
        return cur.endOfWord;
    }
    
    /** Returns if there is any word in the trie that starts with the given prefix. */
    public boolean startsWith(String prefix) {
        TrieNode cur = root;
        for(int i=0; i<prefix.length(); i++){
            char ch = prefix.charAt(i);
            if(cur.children[ch - 'a'] == null) return false;
            cur = cur.children[ch - 'a'];
        }
        return true;
    }
}

/**
 * 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);
 */