[classic algo]-heap sort 堆排序

#include <iostream>
using namespace std;
#define MAXSIZE 10000
int data[MAXSIZE];
int heapSize = 0;

void heapShift(int i) {
int left = i*2+1;
int right = i*2+2;
int largest = i;

if(left < heapSize && data[largest] < data[left]) {
largest = left;
}
if(right < heapSize && data[largest] < data[right]) {
largest = right;
}

if(largest != i) {
int tmp = data[largest];
data[largest] = data[i];
data[i] = tmp;
heapShift(largest);
}
}

void buildHeap(int n)
{
int begin = n/2 - 1;

for(int i = begin; i>=0; --i)
heapShift(i);
}

void heapSort(int n)
{
int tmp;
buildHeap(n);

for(int i=n-1; i>0; --i) {
tmp = data[i];
data[i] = data[0];
data[0] = tmp;
heapSize--;
heapShift(0);
}
}

/*
10
16 14 10 8 7 9 3 2 4 1
*/
int main()
{
int num;
cin>>num;
heapSize = num;
for(int i=0; i<num; ++i)
cin>>data[i];
heapSort(num);
for(int j=0; j<num; ++j)
cout<<data[j]<<" ";

//system(("pause"));
return 0;
}