Algorithm PriorityQueueSort(S, P): Input: A sequence S storing n elements, on which a total order relation is defined, and a priority queue P, that compares keys using the same total order relation Output: The sequence S sorted by the total order relation while !S.isEmpty() do e < S.removeFirst() {remove an element e from S} P.insertItem(e,e) {the key is the element itself} while !P.isEmpty() do e < P.minElement() {get a smallest element from P} P.removeMin() {remove this element from P} S.insertLast(e) {add the element at the end of S} 
Operation 
Output 
Priority Queue 
insertItem(5,A) 
 
{(5,A)} 
insertItem(9,C) 
 
{(5,A),(9,C)} 
insertItem(3,B) 
 
{(3,B),(5,A),(9,C)} 
insertItem(7,D) 
 
{(3,B),(5,A),(7,D),(9,C)} 
minElement() 
B 
{(3,B),(5,A),(7,D),(9,C)} 
minKey() 
3 
{(3,B),(5,A),(7,D),(9,C)} 
removeMin() 
 
{(5,A),(7,D),(9,C)} 
size() 
3 
{(5,A),(7,D),(9,C)} 
minElement() 
A 
{(5,A),(7,D),(9,C)} 
removeMin() 
 
{(7,D),(9,C)} 
removeMin() 
 
{(9,C)} 
removeMin() 
 
{} 
removeMin()  ERROR 
{} 
isEmpty() 
true 
{} 
bool operator<(const Point& p1, const Point& p2)
{ if (p1.getX() == p2.getX()) return p1.getY() < p2.getY();
else return p1.getX() < p1.getX();
}
html7.3 (Compare)class LexCompare {
public:
int operator()(Point a, Point b) {
if (a.x < b.x) return –1
else if (a.x > b.x) return +1
else if (a.y < b.y) return –1
else if (a.y > b.y) return +1
else return 0;
}
};
html7.4 (Generic)Point p(2.3, 4.5);
Point q(1.7, 7.3);
LexCompare lexCompare;
if (lexCompare(p, q) < 0) cout << “p less than q”;
else if (lexCompare(p, q) == 0) cout << “p equals q”;
else if (lexCompare(p, q) > 0) cout << “p greater than q”;





Sequence S 
Priority Queue P (unsorted sequence) 
Input 
(7,4,8,2,5,3,9) 
() 
Phase 1 O(n) 
(4,8,2,5,3,9) (8,2,5,3,9) (2,5,3,9) (5,3,9) (3,9) (9) () 
(7) (7,4) (7,4,8) (7,4,8,2) (7,4,8,2,5) (7,4,8,2,5,3) (7,4,8,2,5,3,9) 
Phase 2 O(n^{2}) 
(2) (2,3) (2,3,4) (2,3,4,5) (2,3,4,5,7) (2,3,4,5,7,8) (2,3,4,5,7,8,9) 
(7,4,8,5,3,9) (7,4,8,5,9) (7,8,5,9) (7,8,9) (8,9) (9) () 

Sequence S 
Priority Queue P (sorted sequence) 
Input 
(7,4,8,2,5,3,9) 
() 
Phase 1 O(n^{2}) 
(4,8,2,5,3,9) (8,2,5,3,9) (2,5,3,9) (5,3,9) (3,9) (9) () 
(7) (4,7) (4,7,8) (2,4,7,8) (2,4,5,7,8) (2,3,4,5,7,8) (2,3,4,5,7,8,9) 
Phase 2 O(n) 
(2) (2,3) (2,3,4) (2,3,4,5) (2,3,4,5,7) (2,3,4,5,7,8) (2,3,4,5,7,8,9) 
(3,4,5,7,8,9) (4,5,7,8,9) (5,7,8,9) (7,8,9) (8,9) (9) () 