AVL树平衡法

Question

我正在尝试实现AVL树，但重新平衡方法似乎无法正常工作。 IDK，如果错误在旋转方法或重新平衡本身。这是代码。

包adt.avltree;

import adt.bst.BSTImpl; import adt.bst.BSTNode;

public class AVLTreeImpl＆gt;     扩展BSTImpl实现AVLTree {

//TODO Do not forget: you must override the methods insert and remove conveniently.

@Override
public void insert(T element) {
    insertRecursive(root, element);
}

private void insertRecursive(BSTNode<T> node, T element) {
    if (node.isEmpty()) {
        node.setData(element);
        node.setLeft(new BSTNode<T>());
        node.setRight(new BSTNode<T>());

    } else {
        if (element.compareTo(node.getData()) < 0) {
            insertRecursive((BSTNode<T>) node.getLeft(), element);
            node.getLeft().setParent(node);
        } else if (element.compareTo(node.getData()) > 0) {
            insertRecursive((BSTNode<T>) node.getRight(), element);
            node.getRight().setParent(node);
        }
        rebalance(node);
    }

}

//AUXILIARY
protected int calculateBalance(BSTNode<T> node){
    if (!node.isEmpty())
        return height((BSTNode<T>) node.getLeft()) - height((BSTNode<T>) node.getRight());
    return 0;
}

//AUXILIARY
protected void rebalance(BSTNode<T> node){
    int balance = calculateBalance(node);
    if (Math.abs(balance) > 1) {
        if (balance == 2) {
            if (calculateBalance((BSTNode<T>) node.getLeft()) == -1)
                leftRotation((BSTNode<T>) node.getLeft());
            rightRotation(node);
        } else if (balance == -2) {
            if (calculateBalance((BSTNode<T>) node.getRight()) == 1)
                rightRotation((BSTNode<T>) node.getRight());
            leftRotation(node);
        }
    }
}

//AUXILIARY
protected void rebalanceUp(BSTNode<T> node){
        // TODO Auto-generated method stub
}

//AUXILIARY
protected void leftRotation(BSTNode<T> node){
    BSTNode<T> pivot = (BSTNode<T>) node.getRight();
    node.setRight(pivot.getLeft());
    node.getRight().setParent(node);
    pivot.setLeft(node);
    pivot.setParent(node.getParent());
    node.setParent(pivot);
    if (node.equals(root))
        root = pivot;
    node = pivot;
}

//AUXILIARY
protected void rightRotation(BSTNode<T> node){
    BSTNode<T> pivot = (BSTNode<T>) node.getLeft();
    node.setLeft(pivot.getRight());
    node.getLeft().setParent(node);
    pivot.setRight(node);
    pivot.setParent(node.getParent());
    node.setParent(pivot);
    if (node.equals(root))
        root = pivot;
    node = pivot;
}


public static void main(String[] args) {
    AVLTreeImpl<Integer> teste = new AVLTreeImpl<Integer>();
    teste.insert(2);
    teste.insert(5);
    teste.insert(3);
    System.out.println(teste.getRoot().getData());
    System.out.println(teste.getRoot().getLeft().getData());
    System.out.println(teste.getRoot().getRight().getData());

}

}

它应该打印3 2 5但是它打印5 2 null