BinarySearchTree.java

package praktikum7;

public class BinaryTree_Example {
    public static void main(String[] args) {
        BinarySearchTree tree = new BinarySearchTree(10);
        tree.add(5);
        tree.add(12);
        tree.add(20);
        tree.preorder(tree.root);
        System.out.println();
        tree.postorder(tree.root);
    }
}

class BinarySearchTree {
    public Node root;

    public BinarySearchTree(int data) {
        root = new Node(data);
    }

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

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

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

    public Node remove(Node current, int data) {
        if (current != null) {
            if (current.data == data) {
                if (current.left != null) current = current.left;
                else current = current.right;
            }
            else if (data < current.data)
                current.left = remove(current.left, data);
            else if (data > current.data)
                current.right = remove(current.right, data);
        }
        return current;
    }

    public void preorder(Node current) {
        // Cetak root, cek kiri, cek kanan
        System.out.print(current.data + " ");
        if (current.left != null) preorder(current.left);
        if (current.right != null) preorder(current.right);
    }

    public void postorder(Node current) {
        // Cek kiri, cek kanan, cetak root
        if (current.left != null) postorder(current.left);
        if (current.right != null) postorder(current.right);
        System.out.print(current.data + " ");
    }
}

class Node {
    public int data;
    public Node left, right;

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