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#include <iostream>
#include <sstream>
using namespace std;
class Heap{
public:
//Build empty heap
Heap();
//Builds a heap from list
Heap(int list[], int listSize);
//not used for this lab
void insert(int x);
//removes the smallest element in the heap
int remove();
//returns the size of the heap;
int size();
private:
//heap is implemented as an array of 25 ints
//better implementation would be a dynamic array
int heap[25];
//number of elements currently in the heap
int heapSize;
//down heap function
void heapify(int location);
//up heap function for insert
void upheaval(int location);
//build heap function used by constructor that takes in array
void buildHeap();
int leftChild(int index);
int rightChild(int index);
int parent(int index);
};
Heap::Heap()
{
heapSize = 0;
}
Heap::Heap(int list[], int listSize)
{
//remember heaps start at 1 not zero
heap[0]=-1;
for(int i=0; i < listSize; i++)
{
heap[i+1] = list[i];
}
heapSize = listSize;
buildHeap();
}
void Heap::insert(int x)
{
//location to insert is heapSize+1
//(Recall, 0th location not used)
heap[heapSize+1] = x;
heapSize++;
//heapsize points to index of last element now
//reheap
upheaval(heapSize);
}
int Heap::remove()
{
int par, rightChild, leftChild;
int index = 0;
par = (index - 1)/2;
leftChild = 2 * index;
rightChild = 2 * index + 1;
if(!heap)
cout << "Heap is Empty";
else
{
heap[0] = heap [heapSize - 1];
heapSize--;
while (heapSize > 0)
{
if( par < leftChild && par > rightChild)
swap (par, leftChild);
else
swap (par, rightChild);
}
}
return heapSize;
}
int Heap::size()
{
return heapSize;
}
void Heap::heapify(int location)
{
int rightChild, leftChild, smallest;
leftChild = 2 * location + 1;
rightChild = 2 * location +2;
if(leftChild <= location)
{
if(leftChild == location)
smallest = leftChild;
else
{
if(heap[leftChild] < heap [rightChild])
smallest = rightChild;
else
smallest = leftChild;
}
if(heap[smallest] > heap[location])
{
swap(heap[smallest], heap[location]);
heapify(smallest);
}
}
//YOUR CODE HERE
}
void Heap::upheaval(int location)
{
int par, r, l;
par = (location - 1)/2;
l = 2 * location;
r = 2 * location + 1;
if (r != location)
{
if (heap[location] > heap[par])
swap(heap[location], heap[par]);
upheaval (location);
}
//coming soon as it gives away the answer to heapify
}
void Heap::buildHeap()
{
}
int Heap::leftChild(int index)
{
return index*2;
}
int Heap::rightChild(int index)
{
return index*2+1;
}
int Heap::parent(int index)
{
return index/2;
}
//not part of the heap class. but uses a heap
void heapSort(int list[], int size)
{
int* temp;
temp = new int[size];
Heap h(list,size);
for(int i=0; i < size; i++)
{
temp[i] = h.remove();
}
for(int j=0; j < size; j++)
{
list[j] = temp[j];
}
}
int main()
{
int testList[] = {34, 5, 23, 12, 33, 98, 4, 13, 44, 37, 1, 86, 8};
int size = 13;
heapSort(testList, size);
cout << "Lists should match " << endl;
cout << "1, 4, 5, 8, 12, 13, 23, 33, 34, 37, 44, 86, 98" << endl;
for(int i=0; i < size; i++)
{
cout << testList[i] << ", ";
}
cout << endl;
}
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Nov 15, 2011 at 2:17am