算法导论 习题6.2-5 用迭代法实现堆排序

#include <iostream>
using namespace std;

void swap(int array[] , int i , int j)
{
array[i] = array[i]+array[j];
array[j] = array[i]-array[j];
array[i] = array[i]-array[j];
}
void MaxHeapify(int array[] , int i , int hSize)
{
int l = 2*i;
int r = 2*i+1;
int largest;
while(l <= hSize)
{
if(array[l] > array[i])
{
largest = l;
}
else
{
largest = i;
}
if(r<=hSize && array[r]>array[largest])       //It's r<=hSize other than r<hSize.
{
largest = r;
}
if(largest != i)
{
swap(array , i ,largest);
i = largest;
l = 2*i;
r = 2*i+1;
}
else
{
break;
}
}
}

void BuildMaxHeap(int array[] , int hSize)
{
for(int i=hSize/2 ; i>=1 ; i--)
{
MaxHeapify(array , i , hSize);
}
}

void HeapSort(int array[] , int length)
{
int hSize = length;
BuildMaxHeap(array , hSize);
for(int i=length ; i>=2 ; i--)
{
swap(array , 1 , i);
hSize--;
MaxHeapify(array , 1 , hSize);
}
}
int main()
{
int a[99];
for(int i=1 ; i<99 ; i++)
{
a[i] = rand()%100;
}
HeapSort(a,99);
for(int i=1 ; i<99 ; i++)
{
cout << a[i] << ' ';
}
return 0;
}