Think about this stuff: private ArrayList elements = new ArrayList(); private Comparator comparator = (E1, E2) -> (E1.compareTo(E2)); public Heap() { super(); elements.add(null); } public Heap(...

Think about this stuff:

private ArrayList elements = new ArrayList<>();
private Comparator comparator = (E1, E2) -> (E1.compareTo(E2));
public Heap() {
super();
elements.add(null);
}
public Heap( Comparator comparator) {
super();
this.comparator = comparator ;
elements.add(null);
}

Complete

int percolateUp(int index)

int percolatDown(int index)

That's right two methods.... Just two.

Also pass the unit tests. Run main for fun and all.