xypor/index.php

/*

** 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