IsEmpty: return true if a priority queue is empty.

ExtractMin: return the element with the minimum cost from a priority queue

Insert: insert an element into a priority queue

Update: update an existing element in a priority queue

Example

#include �PriorityQueue.h�

CTypedPtrHeap<Node> pq;� //initialize the priority queue of integers pq to be empty;

pq.IsEmpty(); //return true;

Node *a,*b,*c; //We assume that the costs in increasing order are a, b, c

pq.Insert(a);� // pq=(a)

pq.Insert(b);� // pq=(a,b)

pq.Insert(c);� // pq=(a,b,c)

Node* d=pq.ExtractMin();� // pq=(b,c); d=a;

//modify c�s key to be the smallest one

pq.Update(c);����� // update pq to reflect c is modifed; pq=(c, b);

pq.IsEmpty(); //return false;