/*************************************************
 * heap.h
 *
 * Header for an implementation of a simple heap, also known as a
 * "priority queue", a partially ordered structure which has quick
 * access to its largest (descending=TRUE) or smallest
 * (descending=FALSE) node.
 *
 * The data contained within the node isn't used by any of the heap
 * functions; use it for any additional information you need to store.
 *
 * Since "struct node_struct" and "struct heap_struct" are defined
 * within heap.c, only routines in heap.c can access its internals
 * directly; from other files that include this header only what's
 * defined by this API is available.
 *
 * Copyright Jim Mahoney (mahoney@marlboro.edu) April 2007
 * This software may be used under the GPL or Artistic license.
 *
 * $Id: heap.h 12567 2007-04-09 16:12:05Z mahoney $
 *************************************************/

#ifndef __HEAP__
#define __HEAP__ 1

// define "bool" type
#include "utility.h"

// "node" and "heap" types.
typedef struct node_struct *node;
typedef struct heap_struct *heap;

// Node creation, getters, and setters.
node new_node(int weight, void* data);
void set_node_data(node n, void* data);
void* get_node_data(node n);
int get_node_weight(node n);

// Heap creation (from an array of nodes) and access to internals.
// descending=TRUE says that pop_heap should return node with largest weight,
// while descending=FALSE means it returns smallest.
heap new_heap(int n_nodes, node* nodes, bool descending);
int get_heap_size(heap h);

// Add a node to a heap.
void push_heap(heap h, node n);     

// Remove and return the node with largest (descending==TRUE) or
// smallest (descending==FALSE) weight.  If size==0, return NULL.
node pop_heap(heap h);

// Measure "steps" in inner loop within new_heap, push_heap, and/or pop_heap
void reset_step_counter();
int get_step_counter();

// Debugging routines.
void print_heap(heap h);
bool heap_check(heap h);  // TRUE => parents and children ordered correctly


#endif