/*		 
 * Copyright (C) 2003-2014 Paolo Boldi and Sebastiano Vigna 
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License. 
 */


package PACKAGE;

#if #keyclass(Object)
import java.util.Arrays;
import java.util.Comparator;

import it.unimi.dsi.fastutil.AbstractPriorityQueue;
#endif

import java.util.NoSuchElementException;


/** A type-specific heap-based priority queue.
 *
 * <P>Instances of this class represent a priority queue using a heap. The heap is enlarged as needed, but
 * it is never shrunk. Use the {@link #trim()} method to reduce its size, if necessary.
 */

public class HEAP_PRIORITY_QUEUE KEY_GENERIC extends ABSTRACT_PRIORITY_QUEUE KEY_GENERIC {

	/** The heap array. */
	SUPPRESS_WARNINGS_KEY_UNCHECKED
	protected KEY_GENERIC_TYPE[] heap = KEY_GENERIC_ARRAY_CAST ARRAYS.EMPTY_ARRAY;

	/** The number of elements in this queue. */
	protected int size;
	
	/** The type-specific comparator used in this queue. */
	protected KEY_COMPARATOR KEY_SUPER_GENERIC c;

	/** Creates a new empty queue with a given capacity and comparator.
	 *
	 * @param capacity the initial capacity of this queue.
	 * @param c the comparator used in this queue, or <code>null</code> for the natural order.
	 */
	SUPPRESS_WARNINGS_KEY_UNCHECKED
	public HEAP_PRIORITY_QUEUE( int capacity, KEY_COMPARATOR KEY_SUPER_GENERIC c ) {
		if ( capacity > 0 ) this.heap = KEY_GENERIC_ARRAY_CAST new KEY_TYPE[ capacity ];
		this.c = c;
	}

	/** Creates a new empty queue with a given capacity and using the natural order.
	 *
	 * @param capacity the initial capacity of this queue.
	 */
	public HEAP_PRIORITY_QUEUE( int capacity ) {
		this( capacity, null );
	}

	/** Creates a new empty queue with a given comparator.
	 *
	 * @param c the comparator used in this queue, or <code>null</code> for the natural order.
	 */
	public HEAP_PRIORITY_QUEUE( KEY_COMPARATOR KEY_SUPER_GENERIC c ) {
		this( 0, c );
	}

	/** Creates a new empty queue using the natural order. 
	 */
	public HEAP_PRIORITY_QUEUE() {
		this( 0, null );
	}

	/** Wraps a given array in a queue using a given comparator.
	 *
	 * <P>The queue returned by this method will be backed by the given array.
	 * The first <code>size</code> element of the array will be rearranged so to form a heap (this is
	 * more efficient than enqueing the elements of <code>a</code> one by one).
	 *
	 * @param a an array.
	 * @param size the number of elements to be included in the queue.
	 * @param c the comparator used in this queue, or <code>null</code> for the natural order.
	 */
	public HEAP_PRIORITY_QUEUE( final KEY_GENERIC_TYPE[] a, int size, final KEY_COMPARATOR KEY_SUPER_GENERIC c ) {
		this( c );
		this.heap = a;
		this.size = size;
		HEAPS.makeHeap( a, size, c );
	}


	/** Wraps a given array in a queue using a given comparator.
	 *
	 * <P>The queue returned by this method will be backed by the given array.
	 * The elements of the array will be rearranged so to form a heap (this is
	 * more efficient than enqueing the elements of <code>a</code> one by one).
	 *
	 * @param a an array.
	 * @param c the comparator used in this queue, or <code>null</code> for the natural order.
	 */
	public HEAP_PRIORITY_QUEUE( final KEY_GENERIC_TYPE[] a, final KEY_COMPARATOR KEY_SUPER_GENERIC c ) {
		this( a, a.length, c );
	}

	/** Wraps a given array in a queue using the natural order.
	 *
	 * <P>The queue returned by this method will be backed by the given array.
	 * The first <code>size</code> element of the array will be rearranged so to form a heap (this is
	 * more efficient than enqueing the elements of <code>a</code> one by one).
	 *
	 * @param a an array.
	 * @param size the number of elements to be included in the queue.
	 */
	public HEAP_PRIORITY_QUEUE( final KEY_GENERIC_TYPE[] a, int size ) {
		this( a, size, null );
	}


	/** Wraps a given array in a queue using the natural order.
	 *
	 * <P>The queue returned by this method will be backed by the given array.
	 * The elements of the array will be rearranged so to form a heap (this is
	 * more efficient than enqueing the elements of <code>a</code> one by one).
	 *
	 * @param a an array.
	 */
	public HEAP_PRIORITY_QUEUE( final KEY_GENERIC_TYPE[] a ) {
		this( a, a.length );
	}

	public void enqueue( KEY_GENERIC_TYPE x ) {
		if ( size == heap.length ) heap = ARRAYS.grow( heap, size + 1 );

		heap[ size++ ] = x;
		HEAPS.upHeap( heap, size, size - 1, c );
	}

	public KEY_GENERIC_TYPE DEQUEUE() {
		if ( size == 0 ) throw new NoSuchElementException();

		final KEY_GENERIC_TYPE result = heap[ 0 ];
		heap[ 0 ] = heap[ --size ];
#if #keyclass(Object)
		heap[ size ] = null;
#endif
		if ( size != 0 ) HEAPS.downHeap( heap, size, 0, c );
		return result;
	}

	public KEY_GENERIC_TYPE FIRST() {
		if ( size == 0 ) throw new NoSuchElementException();
		return heap[ 0 ];
	}

	public void changed() {
		HEAPS.downHeap( heap, size, 0, c );
	}

	public int size() { return size; }

	public void clear() { 
#if #keyclass(Object)
		Arrays.fill( heap, 0, size, null );
#endif
		size = 0; 
	}

	/** Trims the underlying heap array so that it has exactly {@link #size()} elements.
	 */

	public void trim() {
		heap = ARRAYS.trim( heap, size );
	}

	public KEY_COMPARATOR KEY_SUPER_GENERIC comparator() { return c; }


#ifdef TEST

	private static long seed = System.currentTimeMillis(); 
	private static java.util.Random r = new java.util.Random( seed );

	private static KEY_TYPE genKey() {
#if #keyclass(Byte) || #keyclass(Short) || #keyclass(Character)
		return (KEY_TYPE)(r.nextInt());
#elif #keys(primitive)
		return r.NEXT_KEY(); 
#elif #keyclass(Object)
		return Integer.toBinaryString( r.nextInt() );
#else 
		return new java.io.Serializable() {};
#endif
	}

	private static java.text.NumberFormat format = new java.text.DecimalFormat( "#,###.00" );
	private static java.text.FieldPosition p = new java.text.FieldPosition( 0 );

	private static String format( double d ) {
		StringBuffer s = new StringBuffer();
		return format.format( d, s, p ).toString();
	}

	private static void speedTest( int n, boolean comp ) {
		System.out.println( "There are presently no speed tests for this class." );
	}


	private static void fatal( String msg ) {
		System.out.println( msg );
		System.exit( 1 );
	}

	private static void ensure( boolean cond, String msg ) {
		if ( cond ) return;
		fatal( msg );
	}

	private static boolean heapEqual( KEY_TYPE[] a, KEY_TYPE[] b, int sizea, int sizeb ) {
		if ( sizea != sizeb ) return false;
		KEY_TYPE[] aa = (KEY_TYPE[])a.clone();
		KEY_TYPE[] bb = (KEY_TYPE[])b.clone();
		java.util.Arrays.sort( aa, 0, sizea );
		java.util.Arrays.sort( bb, 0, sizeb );
		while( sizea-- != 0 ) if ( ! KEY_EQUALS( aa[sizea], bb[sizea] ) ) return false;
		return true;
	}

	private static KEY_TYPE k[];

	protected static void test( int n ) {
		long ms;
		Exception mThrowsIllegal, tThrowsIllegal, mThrowsOutOfBounds, tThrowsOutOfBounds, mThrowsNoElement, tThrowsNoElement;
		KEY_TYPE rm = KEY_NULL, rt = KEY_NULL;
		k = new KEY_TYPE[ n ];

		for( int i = 0; i < n; i++ ) k[i] = genKey();

		HEAP_PRIORITY_QUEUE m = new HEAP_PRIORITY_QUEUE( COMPARATORS.NATURAL_COMPARATOR );
		ARRAY_PRIORITY_QUEUE t = new ARRAY_PRIORITY_QUEUE( COMPARATORS.NATURAL_COMPARATOR );

		/* We add pairs to t. */
		for( int i = 0; i < n / 2;  i++ ) {
			t.enqueue( k[ i ] );
			m.enqueue( k[ i ] );
		}

		ensure( heapEqual( m.heap, t.array, m.size(), t.size() ), "Error (" + seed + "): m and t differ after creation (" + m + ", " + t + ")" );

		if ( m.size() != 0 ) {
			ensure( KEY_EQUALS(m.FIRST(), t.FIRST()), "Error (" + seed + "): m and t differ in first element after creation (" + m.FIRST() + ", " + t.FIRST() + ")");
		}

		/* Now we add and remove random data in m and t, checking that the result is the same. */

		for(int i=0; i<2*n;  i++ ) {

			if ( r.nextDouble() < 0.01 ) {
				t.clear();
				m.clear();
				for( int j = 0; j < n / 2;  j++ ) {
					t.enqueue( k[ j ] );
					m.enqueue( k[ j ] );
				}
			}

			KEY_TYPE T = genKey();

			mThrowsNoElement = tThrowsNoElement = mThrowsOutOfBounds = tThrowsOutOfBounds = mThrowsIllegal = tThrowsIllegal = null;

			try {
				m.enqueue( T );
			}
			catch ( IndexOutOfBoundsException e ) { mThrowsOutOfBounds = e; }
			catch ( IllegalArgumentException e ) { mThrowsIllegal = e; }

			try {
				t.enqueue( T );
			}
			catch ( IndexOutOfBoundsException e ) { tThrowsOutOfBounds = e; }
			catch ( IllegalArgumentException e ) { tThrowsIllegal = e; }

			ensure( ( mThrowsOutOfBounds == null ) == ( tThrowsOutOfBounds == null ), "Error (" + seed + "): enqueue() divergence in IndexOutOfBoundsException for " + T + " (" + mThrowsOutOfBounds + ", " + tThrowsOutOfBounds + ")" );
			ensure( ( mThrowsIllegal == null ) == ( tThrowsIllegal == null ), "Error (" + seed + "): enqueue() divergence in IllegalArgumentException for " + T + " (" + mThrowsIllegal + ", " + tThrowsIllegal + ")" );

			ensure( heapEqual( m.heap, t.array, m.size(), t.size() ), "Error (" + seed + "): m and t differ after enqueue (" + m + ", " + t + ")" );
			
			if ( m.size() != 0 ) {
				ensure( KEY_EQUALS(m.FIRST(), t.FIRST()), "Error (" + seed + "): m and t differ in first element after enqueue (" + m.FIRST() + ", " + t.FIRST() + ")");
			}

			mThrowsNoElement = tThrowsNoElement = mThrowsOutOfBounds = tThrowsOutOfBounds = mThrowsIllegal = tThrowsIllegal = null;

			try {
				rm = m.DEQUEUE();
			}
			catch ( IndexOutOfBoundsException e ) { mThrowsOutOfBounds = e; }
			catch ( IllegalArgumentException e ) { mThrowsIllegal = e; }
			catch ( NoSuchElementException e ) { mThrowsNoElement = e; }

			try {
				rt = t.DEQUEUE();
			}
			catch ( IndexOutOfBoundsException e ) { tThrowsOutOfBounds = e; }
			catch ( IllegalArgumentException e ) { tThrowsIllegal = e; }
			catch ( NoSuchElementException e ) { tThrowsNoElement = e; }

			ensure( ( mThrowsOutOfBounds == null ) == ( tThrowsOutOfBounds == null ), "Error (" + seed + "): dequeue() divergence in IndexOutOfBoundsException (" + mThrowsOutOfBounds + ", " + tThrowsOutOfBounds + ")" );
			ensure( ( mThrowsIllegal == null ) == ( tThrowsIllegal == null ), "Error (" + seed + "): dequeue() divergence in IllegalArgumentException  (" + mThrowsIllegal + ", " + tThrowsIllegal + ")" );
			ensure( ( mThrowsNoElement == null ) == ( tThrowsNoElement == null ), "Error (" + seed + "): dequeue() divergence in NoSuchElementException  (" + mThrowsNoElement + ", " + tThrowsNoElement + ")" );
			if ( mThrowsOutOfBounds == null ) ensure( rt == rm , "Error (" + seed + "): divergence in dequeue() between t and m (" + rt + ", " + rm + ")" );


			ensure( heapEqual( m.heap, t.array, m.size(), t.size() ), "Error (" + seed + "): m and t differ after dequeue (" + m + ", " + t + ")");
			
			if ( m.size() != 0 ) {
				ensure( KEY_EQUALS(m.FIRST(), t.FIRST()), "Error (" + seed + "): m and t differ in first element after dequeue (" + m.FIRST() + ", " + t.FIRST() + ")");
			}

			HEAP_PRIORITY_QUEUE m2 = new HEAP_PRIORITY_QUEUE( t.array, t.size() );
			ARRAY_PRIORITY_QUEUE t2 = new ARRAY_PRIORITY_QUEUE( m.heap, m.size() );
			m = m2;
			t = t2;

			ensure( heapEqual( m.heap, t.array, m.size(), t.size() ), "Error (" + seed + "): m and t differ after wrap (" + m + ", " + t + ")");
			
			if ( m.size() != 0 ) {
				ensure( KEY_EQUALS(m.FIRST(), t.FIRST()), "Error (" + seed + "): m and t differ in first element after wrap (" + m.FIRST() + ", " + t.FIRST() + ")");
			}

			if ( m.size() != 0 && ( ( new OPEN_HASH_SET( m.heap, 0, m.size ) ).size() == m.size() ) ) {

				int j = t.size(), M = --j;
#if #keys(primitive)
				while( j-- != 0 ) if ( KEY_LESS( t.array[ j ], t.array[ M ] ) ) M = j;
#else
				while( j-- != 0 ) if ( ((Comparable)t.array[ j ]).compareTo( t.array[ M ] )< 0 ) M = j;
#endif

				m.heap[ 0 ] = t.array[ M ] = genKey();

				m.changed();
				t.changed();
				
				ensure( heapEqual( m.heap, t.array, m.size(), t.size() ), "Error (" + seed + "): m and t differ after change (" + m + ", " + t + ")");
				
				if ( m.size() != 0 ) {
					ensure( KEY_EQUALS(m.FIRST(), t.FIRST()), "Error (" + seed + "): m and t differ in first element after change (" + m.FIRST() + ", " + t.FIRST() + ")");
				}
			}
		}


		/* Now we check that m actually holds the same data. */
		  
		m.clear();
		ensure( m.isEmpty(), "Error (" + seed + "): m is not empty after clear()" );

		System.out.println("Test OK");
	}



	public static void main( String args[] ) {
		int n  = Integer.parseInt(args[1]);
		if ( args.length > 2 ) r = new java.util.Random( seed = Long.parseLong( args[ 2 ] ) );
		  

		try {
			if ("speedTest".equals(args[0]) || "speedComp".equals(args[0])) speedTest( n, "speedComp".equals(args[0]) );
			else if ( "test".equals( args[0] ) ) test(n);
		} catch( Throwable e ) {
			e.printStackTrace( System.err );
			System.err.println( "seed: " + seed );
		}
	}

#endif

}
