[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;
}