/**@file   Functions and structures for implementing a minimizing priority queue.   Copyright (C) 2006-2007  Rob Hess <hess@eecs.oregonstate.edu>      @version 1.1.1-20070913*/#ifndef MINPQ_H#define MINPQ_H#include <stdlib.h>/******************************* Defs and macros *****************************//* initial # of priority queue elements for which to allocate space */#define MINPQ_INIT_NALLOCD 512/********************************** Structures *******************************//** an element in a minimizing priority queue */struct pq_node{  void* data;  int key;};/** a minimizing priority queue */struct min_pq{  struct pq_node* pq_array;    /* array containing priority queue */  int nallocd;                 /* number of elements allocated */  int n;                       /**< number of elements in pq */};/*************************** Function Prototypes *****************************//**   Creates a new minimizing priority queue.*/extern struct min_pq* minpq_init();/**  Inserts an element into a minimizing priority queue.  @param min_pq a minimizing priority queue  @param data the data to be inserted  @param key the key to be associated with \a data  @return Returns 0 on success or 1 on failure.*/extern int minpq_insert( struct min_pq* min_pq, void* data, int key );/**   Returns the element of a minimizing priority queue with the smallest key   without removing it from the queue.      @param min_pq a minimizing priority queue      @return Returns the element of \a min_pq with the smallest key or NULL     if \a min_pq is empty*/extern void* minpq_get_min( struct min_pq* min_pq );/**   Removes and returns the element of a minimizing priority queue with the   smallest key.      @param min_pq a minimizing priority queue      @return Returns the element of \a min_pq with the smallest key of NULL     if \a min_pq is empty*/extern void* minpq_extract_min( struct min_pq* min_pq );/**   De-allocates the memory held by a minimizing priorioty queue   @param min_pq pointer to a minimizing priority queue*/extern void minpq_release( struct min_pq** min_pq );#endif