Adding a delete method to a Priority Queue

[kid icarus]

I had to implement a priority queue using binary heaps, which I think I have gotten completed, except for one method. We have implement a delete(Anytype X) method which deletes the object x from the priority queue. (It should return false if x is not in the priority queue, and true otherwise.) Apparently we are supposed to used hash tables to do this, specifically modifying the one found here http://www.cs.uiowa.edu/~kvaradar/sp2009... but we haven't learned about hashing yet, and I am completely at a loss as to how to do it.

Here is my code for the rest of the priority queue though:

public class BinaryHeap<AnyType extends Comparable<? super AnyType>>
{
/**
* Construct the binary heap.
*/
public BinaryHeap( )
{
this( DEFAULT_CAPACITY );
}

/**
* Construct the binary heap.
* @param capacity the capacity of the binary heap.
*/
public BinaryHeap( int capacity )
{
currentSize = 0;
array = (AnyType[]) new Comparable[ capacity + 1 ];
}

/**
* Construct the binary heap given an array of items.
*/
public BinaryHeap( AnyType [ ] items )
{
currentSize = items.length;
array = (AnyType[]) new Comparable[ ( currentSize + 2 ) * 11 / 10 ];

int i = 1;
for( AnyType item : items )
array[ i++ ] = item;
buildHeap( );
}

/**
* Insert into the priority queue, maintaining heap order.
* Duplicates are allowed.
* @param x the item to insert.
*/
public void insert( AnyType x )
{
if( currentSize == array.length - 1 )
enlargeArray( array.length * 2 + 1 );

// Percolate up
int hole = ++currentSize;
for( ; hole > 1 && x.compareTo( array[ hole / 2 ] ) < 0; hole /= 2 )
array[ hole ] = array[ hole / 2 ];
array[ hole ] = x;
}


private void enlargeArray( int newSize )
{
AnyType [] old = array;
array = (AnyType []) new Comparable[ newSize ];
for( int i = 0; i < old.length; i++ )
array[ i ] = old[ i ];
}

/**
* Find the smallest item in the priority queue.
* @return the smallest item, or throw an UnderflowException if empty.
*/
public AnyType findMin( )
{
if( isEmpty( ) )
throw new UnderflowException( );
return array[ 1 ];
}

/**
* Remove the smallest item from the priority queue.
* @return the smallest item, or throw an UnderflowException if empty.
*/
public AnyType deleteMin( )
{
if( isEmpty( ) )
throw new UnderflowException( );

AnyType minItem = findMin( );
array[ 1 ] = array[ currentSize-- ];
percolateDown( 1 );

return minItem;
}

/**
* Establish heap order property from an arbitrary
* arrangement of items. Runs in linear time.
*/
private void buildHeap( )
{
for( int i = currentSize / 2; i > 0; i-- )
percolateDown( i );
}

/**
* Test if the priority queue is logically empty.
* @return true if empty, false otherwise.
*/
public boolean isEmpty( )
{
return currentSize == 0;
}

/**
* Make the priority queue logically empty.
*/
public boolean delete (AnyType x ) {
}
public void makeEmpty( )
{
currentSize = 0;
}

private static final int DEFAULT_CAPACITY = 10;

private int currentSize; // Number of elements in heap
private AnyType [ ] array; // The heap array

/**
* Internal method to percolate down in the heap.
* @param hole the index at which the percolate begins.
*/
private void percolateDown( int hole )
{
int child;
AnyType tmp = array[ hole ];

for( ; hole * 2 <= currentSize; hole = child )
{
child = hole * 2;
if( child != currentSize &&
array[ child + 1 ].compareTo( array[ child ] ) < 0 )
child++;
if( array[ child ].compareTo( tmp ) < 0 )
array[ hole ] = array[ child ];
else
break;
}
array[ hole ] = tmp;
}

// Test program
public static void main( String [ ] args )
{
int numItems = 10000;
BinaryHeap<Integer> h = new BinaryHeap<Integer>( );
int i = 37;

for( i = 37; i != 0; i = ( i + 37 ) % numItems )
h.insert( i );
for( i = 1; i < numItems; i++ )
if( h.deleteMin( ) != i )
System.out.println( "Oops! " + i );
}
}