// joins siblings lists of a and b
private void concatenateSiblings(FibonacciHeapNode a, FibonacciHeapNode b) {
a.nextSibling.prevSibling = b;
b.nextSibling.prevSibling = a;
FibonacciHeapNode origAnext = a.nextSibling;
a.nextSibling = b.nextSibling;
b.nextSibling = origAnext;
}
// makes x's nextSibling and prevSibling point to itself
private void removeFromSiblings(FibonacciHeapNode x) {
if (x.nextSibling == x) return;
x.nextSibling.prevSibling = x.prevSibling;
x.prevSibling.nextSibling = x.nextSibling;
x.nextSibling = x;
x.prevSibling = x;
}
