--- /dev/null
+/* 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. */
+
+/* Fibonacci heaps are somewhat complex, but, there's an
+ article in DDJ on them 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>
+
+typedef struct fibheap
+{
+ size_t nodes;
+ struct fibnode *min;
+ struct fibnode *root;
+} *fibheap_t;
+typedef long fibheapkey_t;
+typedef struct fibnode
+{
+ struct fibnode *parent;
+ struct fibnode *child;
+ struct fibnode *left;
+ struct fibnode *right;
+ unsigned int degree : sizeof(size_t) * CHAR_BIT - 2;
+ unsigned int mark:1;
+ fibheapkey_t key;
+ void *data;
+} *fibnode_t;
+
+extern fibheap_t fibheap_new PARAMS ((void));
+extern fibnode_t fibheap_insert PARAMS ((fibheap_t, fibheapkey_t, void *));
+extern int fibheap_empty PARAMS ((fibheap_t));
+extern fibheapkey_t fibheap_min_key PARAMS ((fibheap_t));
+extern fibheapkey_t fibheap_replace_key PARAMS ((fibheap_t, fibnode_t, fibheapkey_t));
+extern void *fibheap_replace_key_data PARAMS ((fibheap_t, fibnode_t, fibheapkey_t, void *));
+extern void *fibheap_extract_min PARAMS ((fibheap_t));
+extern void *fibheap_min PARAMS ((fibheap_t));
+extern void *fibheap_replace_data PARAMS ((fibheap_t, fibnode_t, void *));
+extern void *fibheap_delete_node PARAMS ((fibheap_t, fibnode_t));
+extern void fibheap_delete PARAMS ((fibheap_t));
+extern fibheap_t fibheap_union PARAMS ((fibheap_t, fibheap_t));
+#endif /* _FIBHEAP_H_ */
--- /dev/null
+
+/* 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. */
+
+/* Fibonacci heaps */
+#include <limits.h>
+#include <stdlib.h>
+#include "libiberty.h"
+#include "fibheap.h"
+
+
+static void fibheap_init PARAMS ((fibheap_t));
+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_init PARAMS ((fibnode_t));
+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 ()
+{
+ fibheap_t result;
+
+ if ((result = xmalloc (sizeof (*result))) == NULL)
+ return NULL;
+
+ fibheap_init (result);
+
+ return result;
+}
+
+/* Initialize the passed in fibonacci heap. */
+static void
+fibheap_init (heap)
+ fibheap_t heap;
+{
+ heap->nodes = 0;
+ heap->min = NULL;
+ heap->root = NULL;
+}
+
+/* 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, if we fail, return NULL. */
+ if ((node = fibnode_new ()) == NULL)
+ return NULL;
+ /* 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 temp;
+
+ /* If one of the heaps is empty, the union is just the other heap. */
+ if (heapa->root == NULL || heapb->root == NULL)
+ {
+ if (heapa->root == NULL)
+ {
+ free (heapa);
+ return heapb;
+ }
+ else
+ {
+ free (heapb);
+ return heapa;
+ }
+ }
+ /* Merge them to the next nodes on the opposite chain. */
+ heapa->root->left->right = heapb->root;
+ heapb->root->left->right = heapa->root;
+ temp = heapa->root->left;
+ heapa->root->left = heapb->root->left;
+ heapb->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;
+
+ 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 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 ret;
+
+ ret = node->key;
+ (void) fibheap_replace_key_data (heap, node, key, node->data);
+
+ 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;
+}
+
+/* Delete NODE from HEAP. */
+void *
+fibheap_delete_node (heap, node)
+ fibheap_t heap;
+ fibnode_t node;
+{
+ void *k;
+ /* To perform delete, we just make it the min key, and extract. */
+ k = node->data;
+ fibheap_replace_key (heap, node, LONG_MIN);
+ fibheap_extract_min (heap);
+
+ return k;
+}
+
+/* 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;
+ fibnode_t x, y, orig;
+
+ ret = heap->min;
+
+ orig = NULL;
+ /* 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; x != orig && x != NULL;)
+ {
+ if (orig == NULL)
+ orig = x;
+ y = x->right;
+ x->parent = NULL;
+ fibheap_ins_root (heap, x);
+ x = y;
+ }
+ /* 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 fibnode_t
+fibnode_new ()
+{
+ fibnode_t e;
+
+ if ((e = xmalloc (sizeof *e)) == NULL)
+ return NULL;
+
+ fibnode_init (e);
+
+ return e;
+}
+
+static void
+fibnode_init (node)
+ fibnode_t node;
+{
+ node->degree = 0;
+ node->mark = 0;
+ node->parent = NULL;
+ node->child = NULL;
+ node->left = node;
+ node->right = node;
+ node->data = NULL;
+}
+
+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;
+}
+
+static 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 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);
+}
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