max-heap.c

File contents

/* Example code */
#include<stdio.h>
#define MAX 16
#define H_SIZE 10
#define parent(i)(i/2)
#define left(i) (2*i)
#define right(i)(2*i+1)

/* Ignore the first 0, since max heap contents start at index 1 */
int a[MAX] = {0,16,4,10,14,7,9,3,2,8,1,};

void  max_heapify(int x[],int i,int h_size){
  int largest, tmp;
  int l=left(i);
  int r=right(i);

  if (l<=h_size &&  x[l]>x[i]) largest=l;
  else  largest=i;
  if(r<=h_size && x[r]>x[largest]) largest=r;
  if (largest!=i)  {
    tmp=x[i];
    x[i]=x[largest];
    x[largest]=tmp;
    max_heapify(x,largest,h_size);
  }
}

int main(){
  int i;
  max_heapify(a,2,H_SIZE);
  for (i=1;i<=H_SIZE;i++) printf("%d ",a[i]);
  return 0;
} /* Output: 16 14 10 8 7 9 3 2 4 1 */