keluarga-pohon-snippet.java

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BinarySearchTree bst = new BinarySearchTree();

        int N = sc.nextInt();
        for (int i = 0; i < N; i++) {
            int data = sc.nextInt();
            bst.insert(data);
        }

        int Q = sc.nextInt();
        for (int i = 0; i < Q; i++) {
            int query = sc.nextInt();
            int parent = bst.getParent(query);
            System.out.println(parent);
        }
    }
}


class BinarySearchTree {
    private Node root;

    public void insert(int data) {
        root = insert(data, root);
    }

    private Node insert(int data, Node current) {
        if (current == null) {
            return new Node(data);
        }
        if (data < current.data) {
            current.left = insert(data, current.left);
        }
        if (data > current.data) {
            current.right = insert(data, current.right);
        }
        return current;
    }

    public int getParent(int data) {
        return getParent(data, root);
    }

    private int getParent(int data, Node current) {
        /* Selamat Mengerjakan! */
    }
}

class Node {
    int data;
    Node left, right;

    public Node(int data) {
        this.data = data;
        this.left = this.right = null;
    }
}