AVL tree rotation in Java

Question

I want to implement the Java AVL tree and to rotate the tree left and right. I am not getting this.

Can anybody by looking at the code below tell me how can I possibly r

Answer 1

Full AVL tree implementation:

public class AVLTree {

    private AVLNode root;

    private static class AVLNode {

        private T t;
        private int height;
        private AVLNode left;
        private AVLNode right;

        private AVLNode(T t) {
            this.t = t;
            height = 1;
        }
    }

    public void insert(T value) {
        root = insert(root, value);
    }

    private AVLNode insert(AVLNode n, T v) {
        if (n == null) {
            n = new AVLNode(v);
            return n;
        } else {
            int k = ((Comparable) n.t).compareTo(v);
            if (k > 0) {
                n.left = insert(n.left, v);
            } else {
                n.right = insert(n.right, v);
            }
            n.height = Math.max(height(n.left), height(n.right)) + 1;
            int heightDiff = heightDiff(n);
            if (heightDiff < -1) {
                if (heightDiff(n.right) > 0) {
                    n.right = rightRotate(n.right);
                    return leftRotate(n);
                } else {
                    return leftRotate(n);
                }
            } else if (heightDiff > 1) {
                if (heightDiff(n.left) < 0) {
                    n.left = leftRotate(n.left);
                    return rightRotate(n);
                } else {
                    return rightRotate(n);
                }
            } else;

        }
        return n;
    }

    private AVLNode leftRotate(AVLNode n) {
        AVLNode r = n.right;
        n.right = r.left;
        r.left = n;
        n.height = Math.max(height(n.left), height(n.right)) + 1;
        r.height = Math.max(height(r.left), height(r.right)) + 1;
        return r;
    }

    private AVLNode rightRotate(AVLNode n) {
        AVLNode r = n.left;
        n.left = r.right;
        r.right = n;
        n.height = Math.max(height(n.left), height(n.right)) + 1;
        r.height = Math.max(height(r.left), height(r.right)) + 1;
        return r;
    }

    private int heightDiff(AVLNode a) {
        if (a == null) {
            return 0;
        }
        return height(a.left) - height(a.right);
    }

    private int height(AVLNode a) {
        if (a == null) {
            return 0;
        }
        return a.height;
    }


}