快速排序算法 - C++实现

快速排序算法 - C++实现

#include <iostream>
using namespace std;

/*quick sort*/
//交换数据
void swap(int &a, int &b)
{
	int temp = a;
	a = b;
	b = temp;
}

//确定关键元素位置并交换
int position(int a[], int l, int r)
{
	int i = l - 1;
	int key = a[r];	//关键元素
	for (int j = l; j <= r; j++)
	{
		if (a[j] < key)
		{
			i++;
			swap(a[i], a[j]);
		}
	}
	swap(a[i+1], a[r]);
	return i+1;
}

//快排
void mySort(int a[], int left, int right)
{
	if (left >= right)
	{
		return;
	}
	int mid = position(a, left, right);
	mySort(a, left, mid - 1);
	mySort(a, mid + 1, right);
}

//主函数测试
int main()
{
	int a[] = {3,6,2,5,1,7,9,8,0,4};
	for (int i = 0; i < 10; i++)
	{
		cout << a[i] << " ";
	}
	cout << endl;
	mySort(a, 0, 9);
	cout << "排序后：" << endl;
	for (int i = 0; i < 10; i++)
        {
                cout << a[i] << " ";
        }
	cout << endl;

	cout << "hello" << endl;
	return 0;
}