dbbf32dd39
version 2.12.0. These bits are taken from the FSF anoncvs repo on 27-January-2002 03:41 PST.
524 lines
11 KiB
C
524 lines
11 KiB
C
/* A Fibonacci heap datatype.
|
||
Copyright 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
|
||
Contributed by Daniel Berlin (dan@cgsoftware.com).
|
||
|
||
This file is part of GNU CC.
|
||
|
||
GNU CC 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.
|
||
|
||
GNU CC 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 GNU CC; see the file COPYING. If not, write to
|
||
the Free Software Foundation, 59 Temple Place - Suite 330,
|
||
Boston, MA 02111-1307, USA. */
|
||
|
||
#ifdef HAVE_CONFIG_H
|
||
#include "config.h"
|
||
#endif
|
||
#ifdef HAVE_LIMITS_H
|
||
#include <limits.h>
|
||
#endif
|
||
#ifdef HAVE_STDLIB_H
|
||
#include <stdlib.h>
|
||
#endif
|
||
#ifdef HAVE_STRING_H
|
||
#include <string.h>
|
||
#endif
|
||
#include "libiberty.h"
|
||
#include "fibheap.h"
|
||
|
||
|
||
#define FIBHEAPKEY_MIN LONG_MIN
|
||
|
||
static void fibheap_ins_root PARAMS ((fibheap_t, fibnode_t));
|
||
static void fibheap_rem_root PARAMS ((fibheap_t, fibnode_t));
|
||
static void fibheap_consolidate PARAMS ((fibheap_t));
|
||
static void fibheap_link PARAMS ((fibheap_t, fibnode_t, fibnode_t));
|
||
static void fibheap_cut PARAMS ((fibheap_t, fibnode_t, fibnode_t));
|
||
static void fibheap_cascading_cut PARAMS ((fibheap_t, fibnode_t));
|
||
static fibnode_t fibheap_extr_min_node PARAMS ((fibheap_t));
|
||
static int fibheap_compare PARAMS ((fibheap_t, fibnode_t, fibnode_t));
|
||
static int fibheap_comp_data PARAMS ((fibheap_t, fibheapkey_t, void *,
|
||
fibnode_t));
|
||
static fibnode_t fibnode_new PARAMS ((void));
|
||
static void fibnode_insert_after PARAMS ((fibnode_t, fibnode_t));
|
||
#define fibnode_insert_before(a, b) fibnode_insert_after (a->left, b)
|
||
static fibnode_t fibnode_remove PARAMS ((fibnode_t));
|
||
|
||
|
||
/* Create a new fibonacci heap. */
|
||
fibheap_t
|
||
fibheap_new ()
|
||
{
|
||
return (fibheap_t) xcalloc (1, sizeof (struct fibheap));
|
||
}
|
||
|
||
/* Create a new fibonacci heap node. */
|
||
static fibnode_t
|
||
fibnode_new ()
|
||
{
|
||
fibnode_t node;
|
||
|
||
node = xcalloc (1, sizeof *node);
|
||
node->left = node;
|
||
node->right = node;
|
||
|
||
return node;
|
||
}
|
||
|
||
static inline int
|
||
fibheap_compare (heap, a, b)
|
||
fibheap_t heap ATTRIBUTE_UNUSED;
|
||
fibnode_t a;
|
||
fibnode_t b;
|
||
{
|
||
if (a->key < b->key)
|
||
return -1;
|
||
if (a->key > b->key)
|
||
return 1;
|
||
return 0;
|
||
}
|
||
|
||
static inline int
|
||
fibheap_comp_data (heap, key, data, b)
|
||
fibheap_t heap;
|
||
fibheapkey_t key;
|
||
void *data;
|
||
fibnode_t b;
|
||
{
|
||
struct fibnode a;
|
||
|
||
a.key = key;
|
||
a.data = data;
|
||
|
||
return fibheap_compare (heap, &a, b);
|
||
}
|
||
|
||
/* Insert DATA, with priority KEY, into HEAP. */
|
||
fibnode_t
|
||
fibheap_insert (heap, key, data)
|
||
fibheap_t heap;
|
||
fibheapkey_t key;
|
||
void *data;
|
||
{
|
||
fibnode_t node;
|
||
|
||
/* Create the new node. */
|
||
node = fibnode_new ();
|
||
|
||
/* Set the node's data. */
|
||
node->data = data;
|
||
node->key = key;
|
||
|
||
/* Insert it into the root list. */
|
||
fibheap_ins_root (heap, node);
|
||
|
||
/* If their was no minimum, or this key is less than the min,
|
||
it's the new min. */
|
||
if (heap->min == NULL || node->key < heap->min->key)
|
||
heap->min = node;
|
||
|
||
heap->nodes++;
|
||
|
||
return node;
|
||
}
|
||
|
||
/* Return the data of the minimum node (if we know it). */
|
||
void *
|
||
fibheap_min (heap)
|
||
fibheap_t heap;
|
||
{
|
||
/* If there is no min, we can't easily return it. */
|
||
if (heap->min == NULL)
|
||
return NULL;
|
||
return heap->min->data;
|
||
}
|
||
|
||
/* Return the key of the minimum node (if we know it). */
|
||
fibheapkey_t
|
||
fibheap_min_key (heap)
|
||
fibheap_t heap;
|
||
{
|
||
/* If there is no min, we can't easily return it. */
|
||
if (heap->min == NULL)
|
||
return 0;
|
||
return heap->min->key;
|
||
}
|
||
|
||
/* Union HEAPA and HEAPB into a new heap. */
|
||
fibheap_t
|
||
fibheap_union (heapa, heapb)
|
||
fibheap_t heapa;
|
||
fibheap_t heapb;
|
||
{
|
||
fibnode_t a_root, b_root, temp;
|
||
|
||
/* If one of the heaps is empty, the union is just the other heap. */
|
||
if ((a_root = heapa->root) == NULL)
|
||
{
|
||
free (heapa);
|
||
return heapb;
|
||
}
|
||
if ((b_root = heapb->root) == NULL)
|
||
{
|
||
free (heapb);
|
||
return heapa;
|
||
}
|
||
|
||
/* Merge them to the next nodes on the opposite chain. */
|
||
a_root->left->right = b_root;
|
||
b_root->left->right = a_root;
|
||
temp = a_root->left;
|
||
a_root->left = b_root->left;
|
||
b_root->left = temp;
|
||
heapa->nodes += heapb->nodes;
|
||
|
||
/* And set the new minimum, if it's changed. */
|
||
if (fibheap_compare (heapa, heapb->min, heapa->min) < 0)
|
||
heapa->min = heapb->min;
|
||
|
||
free (heapb);
|
||
return heapa;
|
||
}
|
||
|
||
/* Extract the data of the minimum node from HEAP. */
|
||
void *
|
||
fibheap_extract_min (heap)
|
||
fibheap_t heap;
|
||
{
|
||
fibnode_t z;
|
||
void *ret = NULL;
|
||
|
||
/* If we don't have a min set, it means we have no nodes. */
|
||
if (heap->min != NULL)
|
||
{
|
||
/* Otherwise, extract the min node, free the node, and return the
|
||
node's data. */
|
||
z = fibheap_extr_min_node (heap);
|
||
ret = z->data;
|
||
free (z);
|
||
}
|
||
|
||
return ret;
|
||
}
|
||
|
||
/* Replace both the KEY and the DATA associated with NODE. */
|
||
void *
|
||
fibheap_replace_key_data (heap, node, key, data)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
fibheapkey_t key;
|
||
void *data;
|
||
{
|
||
void *odata;
|
||
int okey;
|
||
fibnode_t y;
|
||
|
||
/* If we wanted to, we could actually do a real increase by redeleting and
|
||
inserting. However, this would require O (log n) time. So just bail out
|
||
for now. */
|
||
if (fibheap_comp_data (heap, key, data, node) > 0)
|
||
return NULL;
|
||
|
||
odata = node->data;
|
||
okey = node->key;
|
||
node->data = data;
|
||
node->key = key;
|
||
y = node->parent;
|
||
|
||
if (okey == key)
|
||
return odata;
|
||
|
||
/* These two compares are specifically <= 0 to make sure that in the case
|
||
of equality, a node we replaced the data on, becomes the new min. This
|
||
is needed so that delete's call to extractmin gets the right node. */
|
||
if (y != NULL && fibheap_compare (heap, node, y) <= 0)
|
||
{
|
||
fibheap_cut (heap, node, y);
|
||
fibheap_cascading_cut (heap, y);
|
||
}
|
||
|
||
if (fibheap_compare (heap, node, heap->min) <= 0)
|
||
heap->min = node;
|
||
|
||
return odata;
|
||
}
|
||
|
||
/* Replace the DATA associated with NODE. */
|
||
void *
|
||
fibheap_replace_data (heap, node, data)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
void *data;
|
||
{
|
||
return fibheap_replace_key_data (heap, node, node->key, data);
|
||
}
|
||
|
||
/* Replace the KEY associated with NODE. */
|
||
fibheapkey_t
|
||
fibheap_replace_key (heap, node, key)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
fibheapkey_t key;
|
||
{
|
||
int okey = node->key;
|
||
fibheap_replace_key_data (heap, node, key, node->data);
|
||
return okey;
|
||
}
|
||
|
||
/* Delete NODE from HEAP. */
|
||
void *
|
||
fibheap_delete_node (heap, node)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
{
|
||
void *ret = node->data;
|
||
|
||
/* To perform delete, we just make it the min key, and extract. */
|
||
fibheap_replace_key (heap, node, FIBHEAPKEY_MIN);
|
||
fibheap_extract_min (heap);
|
||
|
||
return ret;
|
||
}
|
||
|
||
/* Delete HEAP. */
|
||
void
|
||
fibheap_delete (heap)
|
||
fibheap_t heap;
|
||
{
|
||
while (heap->min != NULL)
|
||
free (fibheap_extr_min_node (heap));
|
||
|
||
free (heap);
|
||
}
|
||
|
||
/* Determine if HEAP is empty. */
|
||
int
|
||
fibheap_empty (heap)
|
||
fibheap_t heap;
|
||
{
|
||
return heap->nodes == 0;
|
||
}
|
||
|
||
/* Extract the minimum node of the heap. */
|
||
static fibnode_t
|
||
fibheap_extr_min_node (heap)
|
||
fibheap_t heap;
|
||
{
|
||
fibnode_t ret = heap->min;
|
||
fibnode_t x, y, orig;
|
||
|
||
/* Attach the child list of the minimum node to the root list of the heap.
|
||
If there is no child list, we don't do squat. */
|
||
for (x = ret->child, orig = NULL; x != orig && x != NULL; x = y)
|
||
{
|
||
if (orig == NULL)
|
||
orig = x;
|
||
y = x->right;
|
||
x->parent = NULL;
|
||
fibheap_ins_root (heap, x);
|
||
}
|
||
|
||
/* Remove the old root. */
|
||
fibheap_rem_root (heap, ret);
|
||
heap->nodes--;
|
||
|
||
/* If we are left with no nodes, then the min is NULL. */
|
||
if (heap->nodes == 0)
|
||
heap->min = NULL;
|
||
else
|
||
{
|
||
/* Otherwise, consolidate to find new minimum, as well as do the reorg
|
||
work that needs to be done. */
|
||
heap->min = ret->right;
|
||
fibheap_consolidate (heap);
|
||
}
|
||
|
||
return ret;
|
||
}
|
||
|
||
/* Insert NODE into the root list of HEAP. */
|
||
static void
|
||
fibheap_ins_root (heap, node)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
{
|
||
/* If the heap is currently empty, the new node becomes the singleton
|
||
circular root list. */
|
||
if (heap->root == NULL)
|
||
{
|
||
heap->root = node;
|
||
node->left = node;
|
||
node->right = node;
|
||
return;
|
||
}
|
||
|
||
/* Otherwise, insert it in the circular root list between the root
|
||
and it's right node. */
|
||
fibnode_insert_after (heap->root, node);
|
||
}
|
||
|
||
/* Remove NODE from the rootlist of HEAP. */
|
||
static void
|
||
fibheap_rem_root (heap, node)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
{
|
||
if (node->left == node)
|
||
heap->root = NULL;
|
||
else
|
||
heap->root = fibnode_remove (node);
|
||
}
|
||
|
||
/* Consolidate the heap. */
|
||
static void
|
||
fibheap_consolidate (heap)
|
||
fibheap_t heap;
|
||
{
|
||
fibnode_t a[1 + 8 * sizeof (long)];
|
||
fibnode_t w;
|
||
fibnode_t y;
|
||
fibnode_t x;
|
||
int i;
|
||
int d;
|
||
int D;
|
||
|
||
D = 1 + 8 * sizeof (long);
|
||
|
||
memset (a, 0, sizeof (fibnode_t) * D);
|
||
|
||
while ((w = heap->root) != NULL)
|
||
{
|
||
x = w;
|
||
fibheap_rem_root (heap, w);
|
||
d = x->degree;
|
||
while (a[d] != NULL)
|
||
{
|
||
y = a[d];
|
||
if (fibheap_compare (heap, x, y) > 0)
|
||
{
|
||
fibnode_t temp;
|
||
temp = x;
|
||
x = y;
|
||
y = temp;
|
||
}
|
||
fibheap_link (heap, y, x);
|
||
a[d] = NULL;
|
||
d++;
|
||
}
|
||
a[d] = x;
|
||
}
|
||
heap->min = NULL;
|
||
for (i = 0; i < D; i++)
|
||
if (a[i] != NULL)
|
||
{
|
||
fibheap_ins_root (heap, a[i]);
|
||
if (heap->min == NULL || fibheap_compare (heap, a[i], heap->min) < 0)
|
||
heap->min = a[i];
|
||
}
|
||
}
|
||
|
||
/* Make NODE a child of PARENT. */
|
||
static void
|
||
fibheap_link (heap, node, parent)
|
||
fibheap_t heap ATTRIBUTE_UNUSED;
|
||
fibnode_t node;
|
||
fibnode_t parent;
|
||
{
|
||
if (parent->child == NULL)
|
||
parent->child = node;
|
||
else
|
||
fibnode_insert_before (parent->child, node);
|
||
node->parent = parent;
|
||
parent->degree++;
|
||
node->mark = 0;
|
||
}
|
||
|
||
/* Remove NODE from PARENT's child list. */
|
||
static void
|
||
fibheap_cut (heap, node, parent)
|
||
fibheap_t heap;
|
||
fibnode_t node;
|
||
fibnode_t parent;
|
||
{
|
||
fibnode_remove (node);
|
||
parent->degree--;
|
||
fibheap_ins_root (heap, node);
|
||
node->parent = NULL;
|
||
node->mark = 0;
|
||
}
|
||
|
||
static void
|
||
fibheap_cascading_cut (heap, y)
|
||
fibheap_t heap;
|
||
fibnode_t y;
|
||
{
|
||
fibnode_t z;
|
||
|
||
while ((z = y->parent) != NULL)
|
||
{
|
||
if (y->mark == 0)
|
||
{
|
||
y->mark = 1;
|
||
return;
|
||
}
|
||
else
|
||
{
|
||
fibheap_cut (heap, y, z);
|
||
y = z;
|
||
}
|
||
}
|
||
}
|
||
|
||
static void
|
||
fibnode_insert_after (a, b)
|
||
fibnode_t a;
|
||
fibnode_t b;
|
||
{
|
||
if (a == a->right)
|
||
{
|
||
a->right = b;
|
||
a->left = b;
|
||
b->right = a;
|
||
b->left = a;
|
||
}
|
||
else
|
||
{
|
||
b->right = a->right;
|
||
a->right->left = b;
|
||
a->right = b;
|
||
b->left = a;
|
||
}
|
||
}
|
||
|
||
static fibnode_t
|
||
fibnode_remove (node)
|
||
fibnode_t node;
|
||
{
|
||
fibnode_t ret;
|
||
|
||
if (node == node->left)
|
||
ret = NULL;
|
||
else
|
||
ret = node->left;
|
||
|
||
if (node->parent != NULL && node->parent->child == node)
|
||
node->parent->child = ret;
|
||
|
||
node->right->left = node->left;
|
||
node->left->right = node->right;
|
||
|
||
node->parent = NULL;
|
||
node->left = node;
|
||
node->right = node;
|
||
|
||
return ret;
|
||
}
|