/* A Fibonacci heap datatype.

   Copyright (C) 1998-2018 Free Software Foundation, Inc.

   Contributed by Daniel Berlin (dan@cgsoftware.com).

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it

under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2, or (at your option)

any later version.

GCC is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with GCC; see the file COPYING.  If not, write to

the Free Software Foundation, 51 Franklin Street - Fifth Floor,

Boston, MA 02110-1301, USA.  */

/* Fibonacci heaps are somewhat complex, but, there's an article in

   DDJ that explains them pretty well:

   http://www.ddj.com/articles/1997/9701/9701o/9701o.htm?topic=algoritms

   Introduction to algorithms by Corman and Rivest also goes over them.

   The original paper that introduced them is "Fibonacci heaps and their

   uses in improved network optimization algorithms" by Tarjan and

   Fredman (JACM 34(3), July 1987).

   Amortized and real worst case time for operations:

   ExtractMin: O(lg n) amortized. O(n) worst case.

   DecreaseKey: O(1) amortized.  O(lg n) worst case. 

   Insert: O(2) amortized. O(1) actual.  

   Union: O(1) amortized. O(1) actual.  */

#ifndef _FIBHEAP_H_

#define _FIBHEAP_H_

#include "ansidecl.h"

#ifdef __cplusplus

extern "C" {

#endif

typedef long fibheapkey_t;

typedef struct fibheap

{

  size_t nodes;

  struct fibnode *min;

  struct fibnode *root;

} *fibheap_t;

typedef struct fibnode

{

  struct fibnode *parent;

  struct fibnode *child;

  struct fibnode *left;

  struct fibnode *right;

  fibheapkey_t key;

  void *data;

#if defined (__GNUC__) && (!defined (SIZEOF_INT) || SIZEOF_INT < 4)

  __extension__ unsigned long int degree : 31;

  __extension__ unsigned long int mark : 1;

#else

  unsigned int degree : 31;

  unsigned int mark : 1;

#endif

} *fibnode_t;

extern fibheap_t fibheap_new (void);

extern fibnode_t fibheap_insert (fibheap_t, fibheapkey_t, void *);

extern int fibheap_empty (fibheap_t);

extern fibheapkey_t fibheap_min_key (fibheap_t);

extern fibheapkey_t fibheap_replace_key (fibheap_t, fibnode_t,

                                         fibheapkey_t);

extern void *fibheap_replace_key_data (fibheap_t, fibnode_t,

                                       fibheapkey_t, void *);

extern void *fibheap_extract_min (fibheap_t);

extern void *fibheap_min (fibheap_t);

extern void *fibheap_replace_data (fibheap_t, fibnode_t, void *);

extern void *fibheap_delete_node (fibheap_t, fibnode_t);

extern void fibheap_delete (fibheap_t);

extern fibheap_t fibheap_union (fibheap_t, fibheap_t);

#ifdef __cplusplus

}

#endif

#endif /* _FIBHEAP_H_ */