cPractice/heapSort.c at main · AedenThomas/cPractice · GitHub

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// Sort a given set of elements using the Heap sort method.

#include<stdio.h>

void heapify(int arr[], int n, int i)
{
    int largest = i;
    int l = 2 * i + 1;
    int r = 2 * i + 2;

    if (l < n && arr[l] > arr[largest])
        largest = l;

    if (r < n && arr[r] > arr[largest])
        largest = r;

    if (largest != i)
    {
        int swap = arr[i];
        arr[i] = arr[largest];
        arr[largest] = swap;

        heapify(arr, n, largest);
    }
}

void heapSort(int arr[], int n)
{
    for (int i = n / 2 - 1; i >= 0; i--)
        heapify(arr, n, i);

    for (int i=n-1; i>=0; i--)
    {
        int swap = arr[0];
        arr[0] = arr[i];
        arr[i] = swap;

        heapify(arr, i, 0);
    }
}

void printArray(int arr[], int size)
{
    int i;
    for (i=0; i < size; i++)
        printf("%d ", arr[i]);
    printf("\n");
}

int main()
{
    int arr[] = {10, 12, 11, 13, 5, 6, 7};
    int n = sizeof(arr)/sizeof(arr[0]);

    heapSort(arr, n);

    printf("Sorted array is \n");
    printArray(arr, n);

    return 0;
}