text: /**
  Copyright 2017 Google Inc. All Rights Reserved.
  
  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.
  
  */
  
  /*
   * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
   * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice including the dates of first publication and
   * either this permission notice or a reference to
   * http://oss.sgi.com/projects/FreeB/
   * shall be included in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
   * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
   * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   * Except as contained in this notice, the name of Silicon Graphics, Inc.
   * shall not be used in advertising or otherwise to promote the sale, use or
   * other dealings in this Software without prior written authorization from
   * Silicon Graphics, Inc.
   */
  /*
  ** Author: Eric Veach, July 1994.
  **
  */
  
  #ifndef __priorityq_sort_h_
  #define __priorityq_sort_h_
  
  #include "priorityq-heap.h"
  
  #undef PQkey
  #undef PQhandle
  #undef PriorityQ
  #undef pqNewPriorityQ
  #undef pqDeletePriorityQ
  #undef pqInit
  #undef pqInsert
  #undef pqMinimum
  #undef pqExtractMin
  #undef pqDelete
  #undef pqIsEmpty
  
  /* Use #define's so that another heap implementation can use this one */
  
  #define PQkey			PQSortKey
  #define PQhandle		PQSortHandle
  #define PriorityQ		PriorityQSort
  
  #define pqNewPriorityQ(leq)	__gl_pqSortNewPriorityQ(leq)
  #define pqDeletePriorityQ(pq)	__gl_pqSortDeletePriorityQ(pq)
  
  /* The basic operations are insertion of a new key (pqInsert),
   * and examination/extraction of a key whose value is minimum
   * (pqMinimum/pqExtractMin).  Deletion is also allowed (pqDelete);
   * for this purpose pqInsert returns a "handle" which is supplied
   * as the argument.
   *
   * An initial heap may be created efficiently by calling pqInsert
   * repeatedly, then calling pqInit.  In any case pqInit must be called
   * before any operations other than pqInsert are used.
   *
   * If the heap is empty, pqMinimum/pqExtractMin will return a NULL key.
   * This may also be tested with pqIsEmpty.
   */
  #define pqInit(pq)		__gl_pqSortInit(pq)
  #define pqInsert(pq,key)	__gl_pqSortInsert(pq,key)
  #define pqMinimum(pq)		__gl_pqSortMinimum(pq)
  #define pqExtractMin(pq)	__gl_pqSortExtractMin(pq)
  #define pqDelete(pq,handle)	__gl_pqSortDelete(pq,handle)
  #define pqIsEmpty(pq)		__gl_pqSortIsEmpty(pq)
  
  
  /* Since we support deletion the data structure is a little more
   * complicated than an ordinary heap.  "nodes" is the heap itself;
   * active nodes are stored in the range 1..pq->size.  When the
   * heap exceeds its allocated size (pq->max), its size doubles.
   * The children of node i are nodes 2i and 2i+1.
   *
   * Each node stores an index into an array "handles".  Each handle
   * stores a key, plus a pointer back to the node which currently
   * represents that key (ie. nodes[handles[i].node].handle == i).
   */
  
  typedef PQHeapKey PQkey;
  typedef PQHeapHandle PQhandle;
  typedef struct PriorityQ PriorityQ;
  
  struct PriorityQ {
    PriorityQHeap	*heap;
    PQkey		*keys;
    PQkey		**order;
    PQhandle	size, max;
    int		initialized;
    int		(*leq)(PQkey key1, PQkey key2);
  };
    
  PriorityQ	*pqNewPriorityQ( int (*leq)(PQkey key1, PQkey key2) );
  void		pqDeletePriorityQ( PriorityQ *pq );
  
  int		pqInit( PriorityQ *pq );
  PQhandle	pqInsert( PriorityQ *pq, PQkey key );
  PQkey		pqExtractMin( PriorityQ *pq );
  void		pqDelete( PriorityQ *pq, PQhandle handle );
  
  PQkey		pqMinimum( PriorityQ *pq );
  int		pqIsEmpty( PriorityQ *pq );
  
  #endif
  