/** x y / \ / \ A y => x C / \ / \ B C A B */
private void leftRotate(Node<T> x) {
Node<T> parent = x.parent;
Node<T> y = x.right;
Node<T> B = y.left;
y.left = x;
x.parent = y;
x.right = B;
if (B != null) B.parent = x;
y.parent = parent;
if (parent != null) {
parent.replaceChild(x, y);
} else {
root = y;
}
updateHeight(x);
}
/** x x x x \ \ / / y y y y \ / / \ z z z z */
private void balance(Node<T> x, Node<T> y) {
if (!x.isBalanced()) {
if (x.right != null && x.right == y) {
if (y.isRightHeavy()) {
leftRotate(x);
} else if (y.isLeftHeavy()) {
rightRotate(y);
leftRotate(x);
}
}
if (x.left != null & x.left == y) {
if (y.isLeftHeavy()) {
rightRotate(x);
} else if (y.isRightHeavy()) {
leftRotate(y);
rightRotate(x);
}
}
}
if (x.parent != null) balance(x.parent, x);
}
private void addToRight(Node<T> parent, Node<T> newNode) {
countNodes++;
parent.right = newNode;
newNode.parent = parent;
}
private void updateHeight(Node<T> node) {
while (node != null) {
node.updateHeight();
node = node.parent;
}
}
private void addToLeft(Node<T> parent, Node<T> newNode) {
countNodes++;
parent.left = newNode;
newNode.parent = parent;
}