堆排序(Heap Sort)

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#define MAX 10

void maxHeapify(int *arr, int i, int size)
{
  int l = (i + 1) * 2 - 1;
  int r = (i + 1) * 2;
  int largest, t;
  if (l + 1 <= size && arr[l] > arr[i])
    largest = l;
  else
    largest = i;
  if (r + 1 <= size && arr[r] > arr[largest])
    largest = r;
  if (largest != i)
  {
    t = arr[i];
    arr[i] = arr[largest];
    arr[largest] = t;
    maxHeapify(arr, largest, size);
  }
}

void buildMaxHeap(int *arr, int size)
{
  int i;
  for (i = size / 2 - 1; i >= 0; i--)
    maxHeapify(arr, i, size);
}

void heapSort(int *arr, int size)
{
  buildMaxHeap(arr, size);
  int i, t;
  for (i = size - 1; i >= 1; i--)
  { i = size - 1;
    t = arr[0];
    arr[0] = arr[i];
    arr[i] = t;

    size--;
    maxHeapify(arr, 0, size);
  }
}

int main(int argc, const char *argv[])
{
  int arr[MAX];
  int i;
  srand((unsigned)time(NULL));
  for (i = 0; i < MAX; i++)
    arr[i] = rand() % MAX;
  printf("original array :");
  for (i = 0; i < sizeof(arr) / sizeof(int); i++)
    printf("%d ", arr[i]);
  printf("\n");
  heapSort(arr, sizeof(arr) / sizeof(int));
  printf("sorted array   :");
  for (i = 0; i < sizeof(arr) / sizeof(int); i++)
    printf("%d ", arr[i]);
  printf("\n");
  return 0;
}