堆排序

#include <iostream>

using namespace std;

void sift(int a[], int k, int m)
{
    int i = k;
    int j = 2 * i + 1;

    while (j < m-1)
    {
        if (j < m-1 && a[j] < a[j+1]) j++;
        if (a[i] > a[j]) break;
        else
        {
            int temp = a[i];
            a[i] = a[j];
            a[j] = temp;
            i = j;
            j = 2 * i + 1;
        }
    }
}

void heapsort(int a[], int n)
{
    int i = 0;
    int j = 0;

    for (i = n/2; i>=0; i--)
        sift(a, i, n);

    for (j = 1; j < n; j++)
    {
        int temp = a[0];
        a[0] = a[n-j];
        a[n-j] = temp;
        sift(a, 0, n-j);
    }
}

int main(void)
{
    int k = 0;
    int a[11] = {10, 4, 9, 40, 11, 66, 32, 21, 99, 33, 6};
    heapsort(a, 11);
    for (k = 0; k < 11; k++)
        printf ("%d\t", a[k]);

    printf ("\n");

    return 0;
}