C++ Programming Code Examples
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C++ Program to Implement Heap Sort
/* C++ Program to Implement Heap Sort
This is a C++ program to sort the given data using Heap Sort.
- Heap sort is a comparison based algorithm.
- It is improved version of selection sort.
- The time complexity is O(n*log(n)).
- Build a max heap using the given data element.
- Delete the root node repeatedly.
- Store the node at the end of the array.
- Display the result.
- Exit. */
#include <iostream>
using namespace std;
// A function to heapify the array.
void MaxHeapify(int a[], int i, int n)
{
int j, temp;
temp = a[i];
j = 2*i;
while (j <= n)
{
if (j < n && a[j+1] > a[j])
j = j+1;
// Break if parent value is already greater than child value.
if (temp > a[j])
break;
// Switching value with the parent node if temp < a[j].
else if (temp <= a[j])
{
a[j/2] = a[j];
j = 2*j;
}
}
a[j/2] = temp;
return;
}
void HeapSort(int a[], int n)
{
int i, temp;
for (i = n; i >= 2; i--)
{
// Storing maximum value at the end.
temp = a[i];
a[i] = a[1];
a[1] = temp;
// Building max heap of remaining element.
MaxHeapify(a, 1, i - 1);
}
}
void Build_MaxHeap(int a[], int n)
{
int i;
for(i = n/2; i >= 1; i--)
MaxHeapify(a, i, n);
}
int main()
{
int n, i;
cout<<"\nEnter the number of data element to be sorted: ";
cin>>n;
n++;
int arr[n];
for(i = 1; i < n; i++)
{
cout<<"Enter element "<<i<<": ";
cin>>arr[i];
}
// Building max heap.
Build_MaxHeap(arr, n-1);
HeapSort(arr, n-1);
// Printing the sorted data.
cout<<"\nSorted Data ";
for (i = 1; i < n; i++)
cout<<"->"<<arr[i];
return 0;
}
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