private AANode<T> remove(T element, AANode<T> node) {
if (node == null) {
return node;
} else if (element.compareTo(node.getValue()) > 0) {
node.setRight(remove(element, node.getRight()));
} else if (element.compareTo(node.getValue()) < 0) {
node.setLeft(remove(element, node.getLeft()));
} else {
if (node.getLevel() == 1) {
return null;
} else if (node.getLeft() == null) {
AANode<T> left = getSuccessor(node);
node.setRight(remove(left.getValue(), node.getRight()));
node.setValue(left.getValue());
} else {
AANode<T> left = getPredecessor(node);
node.setLeft(remove(left.getValue(), node.getLeft()));
node.setValue(left.getValue());
}
}
node = decreaseLevel(node);
node = skew(node);
node.setRight(skew(node.getRight()));
if (node.getRight() != null) {
node.getRight().setRight(skew(node.getRight().getRight()));
}
node = split(node);
node.setRight(split(node).getRight());
return node;
}
private AANode<T> split(AANode<T> node) {
if (node == null) {
return null;
} else if (node.getLeft() == null) {
return node;
} else if (node.getLeft().getLevel() == node.getLevel()) {
AANode<T> left = node.getLeft();
node.setLeft(left.getRight());
left.setRight(node);
return left;
} else {
return node;
}
}
private AANode<T> skew(AANode<T> node) {
if (node == null) {
return null;
} else if (node.getRight() == null || node.getRight().getRight() == null) {
return node;
} else if (node.getLevel() == node.getRight().getRight().getLevel()) {
AANode<T> right = node.getRight();
node.setRight(right.getLeft());
right.setLeft(node);
right.setLevel(right.getLevel() + 1);
return right;
} else {
return node;
}
}
private AANode<T> insert(T element, AANode<T> node) {
if (node == null) {
node = new AANode<>(element);
} else if (element.compareTo(node.getValue()) < 0) {
node.setLeft(insert(element, node.getLeft()));
} else if (element.compareTo(node.getValue()) > 0) {
node.setRight(insert(element, node.getRight()));
} else {
return node;
}
node = skew(node);
node = split(node);
return node;
}