Enhancing Informed Search

Open and Closed can be implemented using java.util.Hashtable.
- However, classes implementing State, for example, BlockState, must override the Object class's hashCode method.
Priority queue "promotion" is not offered by java.util.PriorityQueue.
- However, it can be faked by removing from the priority queue and then adding the same state with a new key.
- A more efficient promotion operation can be implemented in your BinaryHeap class by decreasing a node's key and then successively swapping places with its parent as when a new node is added.

Implementation Notes