Slide 1

Heaps as a Abstract Data Type

Samples of Max Heaps

Samples of Min Heaps

Example Max Heap Object Methods

	Construct (initialize) a max heap object using data elements of an array ‘A’
	Build a max heap object from an array ‘A’ of n data elements
	Destroy (delete) a heap object and an array ‘A’
	Compare data elements
	Swap data elements
	Rebuild a max heap
	Add/insert an element into a max heap object
	Delete an element from a max heap object
	Do a heap sort for an array ‘A’ using a max heap object
	Display (print) a heap object at each iteration of heap sort
	Print a max heap object

Creation of a Heap

	#define MAX_ELEMENTS 200 /* maximum heap size */
	/* note: the heap is defined in an array that goes from index value 0 to index value MAX_ELEMENTS – 1.  The parameter n keeps track of the next index slot where one can insert a new element into the heap */
	#define HEAP_FULL(n) (n == MAX_ELEMENTS)
	#define HEAP_EMPTY(n) (!n)
	typedef struct (
	int key;
	/* other fields   */
	) element;
	element heap(MAX_ELEMENTS) ;
	int n = 0;

Insertion into a max heap

Slide 8

Algorithm for inserting into a max_heap

	Insert max_heap (element, next_pos_avail)
	Put element at the end of the heap (in next_pos_avail);
	While element is not the root and element > parent
	Swap element with its parent

"Void insert_max_heap(element item,"

	Void insert_max_heap(element item, int * n) {/* insert item into a max heap of current size *n  */ int i; if (HEAP_FULL(*n)){ fprintf(stderr, “The heap is full. \n”); exit(1);}
	i = (*n); while((i != 0)
	&& (item.key > heap[(ROUND(i/2)-1)].key))
	{heap[i] = heap[(ROUND(i/2)-1)];
	i  = ROUND(i/2) -1;} heap[i] = item; }