/**
* Heapify up the treap at the current node to the root.
*
* @param current to heapify.
*/
private void heapify(TreapNode<T> current) {
// Bubble up the heap, if needed
TreapNode<T> parent = (TreapNode<T>) current.parent;
while (parent != null && current.priority > parent.priority) {
Node<T> grandParent = parent.parent;
if (grandParent != null) {
if (grandParent.greater != null && grandParent.greater.equals(parent)) {
// My parent is my grandparents greater branch
grandParent.greater = current;
current.parent = grandParent;
} else if (grandParent.lesser != null && grandParent.lesser.equals(parent)) {
// My parent is my grandparents lesser branch
grandParent.lesser = current;
current.parent = grandParent;
} else {
System.err.println(
"YIKES! Grandparent should have at least one non-NULL child which should be my parent.");
}
current.parent = grandParent;
} else {
root = current;
root.parent = null;
}
if (parent.lesser != null && parent.lesser.equals(current)) {
// LEFT
parent.lesser = null;
if (current.greater == null) {
current.greater = parent;
parent.parent = current;
} else {
Node<T> lost = current.greater;
current.greater = parent;
parent.parent = current;
parent.lesser = lost;
lost.parent = parent;
}
} else if (parent.greater != null && parent.greater.equals(current)) {
// RIGHT
parent.greater = null;
if (current.lesser == null) {
current.lesser = parent;
parent.parent = current;
} else {
Node<T> lost = current.lesser;
current.lesser = parent;
parent.parent = current;
parent.greater = lost;
lost.parent = parent;
}
} else {
// We really shouldn't get here
System.err.println(
"YIKES! Parent should have at least one non-NULL child which should be me.");
}
parent = (TreapNode<T>) current.parent;
}
}
