1 /* A Fibonacci heap datatype.
2    Copyright (C) 1998-2016 Free Software Foundation, Inc.
3    Contributed by Daniel Berlin (dan@cgsoftware.com).
4 
5 This file is part of GCC.
6 
7 GCC is free software; you can redistribute it and/or modify it
8 under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
10 any later version.
11 
12 GCC is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING.  If not, write to
19 the Free Software Foundation, 51 Franklin Street - Fifth Floor,
20 Boston, MA 02110-1301, USA.  */
21 
22 /* Fibonacci heaps are somewhat complex, but, there's an article in
23    DDJ that explains them pretty well:
24 
25    http://www.ddj.com/articles/1997/9701/9701o/9701o.htm?topic=algoritms
26 
27    Introduction to algorithms by Corman and Rivest also goes over them.
28 
29    The original paper that introduced them is "Fibonacci heaps and their
30    uses in improved network optimization algorithms" by Tarjan and
31    Fredman (JACM 34(3), July 1987).
32 
33    Amortized and real worst case time for operations:
34 
35    ExtractMin: O(lg n) amortized. O(n) worst case.
36    DecreaseKey: O(1) amortized.  O(lg n) worst case.
37    Insert: O(2) amortized. O(1) actual.
38    Union: O(1) amortized. O(1) actual.  */
39 
40 #ifndef _FIBHEAP_H_
41 #define _FIBHEAP_H_
42 
43 #include "ansidecl.h"
44 
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48 
49 typedef long fibheapkey_t;
50 
51 typedef struct fibheap
52 {
53   size_t nodes;
54   struct fibnode *min;
55   struct fibnode *root;
56 } *fibheap_t;
57 
58 typedef struct fibnode
59 {
60   struct fibnode *parent;
61   struct fibnode *child;
62   struct fibnode *left;
63   struct fibnode *right;
64   fibheapkey_t key;
65   void *data;
66 #if defined (__GNUC__) && (!defined (SIZEOF_INT) || SIZEOF_INT < 4)
67   __extension__ unsigned long int degree : 31;
68   __extension__ unsigned long int mark : 1;
69 #else
70   unsigned int degree : 31;
71   unsigned int mark : 1;
72 #endif
73 } *fibnode_t;
74 
75 extern fibheap_t fibheap_new (void);
76 extern fibnode_t fibheap_insert (fibheap_t, fibheapkey_t, void *);
77 extern int fibheap_empty (fibheap_t);
78 extern fibheapkey_t fibheap_min_key (fibheap_t);
79 extern fibheapkey_t fibheap_replace_key (fibheap_t, fibnode_t,
80                                          fibheapkey_t);
81 extern void *fibheap_replace_key_data (fibheap_t, fibnode_t,
82                                        fibheapkey_t, void *);
83 extern void *fibheap_extract_min (fibheap_t);
84 extern void *fibheap_min (fibheap_t);
85 extern void *fibheap_replace_data (fibheap_t, fibnode_t, void *);
86 extern void *fibheap_delete_node (fibheap_t, fibnode_t);
87 extern void fibheap_delete (fibheap_t);
88 extern fibheap_t fibheap_union (fibheap_t, fibheap_t);
89 
90 #ifdef __cplusplus
91 }
92 #endif
93 
94 #endif /* _FIBHEAP_H_ */
95