Trie.java

package data_structures.tries;

public class Trie {
    private TrieNode root;
    public Trie() {
        root = new TrieNode();
        root.val = '\0';
    }

    public void insert(String word) {
        TrieNode ws = root;
        for(int i = 0; i < word.length(); i++){
            char c = word.charAt(i);
            if(ws.children[c - 'a'] == null){
                ws.children[c - 'a'] = new TrieNode(c);
            }
            ws = ws.children[c - 'a'];
        }
        ws.isWord = true;
    }

    public boolean search(String word) {
        TrieNode ws = root;
        for(char c: word.toCharArray()){
            if(ws.children[c - 'a'] == null) return false;
            ws = ws.children[c - 'a'];
        }
        return ws.isWord;
    }

    public boolean startsWith(String prefix) {
        TrieNode ws = root;
        for(char c: prefix.toCharArray()){
            if(ws.children[c - 'a'] == null) return false;
            ws = ws.children[c - 'a'];
        }
        return true;
    }
}