快速排序(某公司社招面试试题)

      快速排序是对冒泡排序的改进，算法代码如下：

 

#include<iostream>
using namespace std;

int partition(int a[], int low, int high) //划分
{
	int pivotKey = a[low];
	while(low < high)
	{
		while(low < high && a[high] >= pivotKey)
			high--;
		a[low] = a[high];
		while(low < high && a[low] <= pivotKey)	
			low++;
		a[high] = a[low];
	}
	a[low] = pivotKey; //恢复
	return low;
}

void quickSort(int a[], int low, int high)
{
	int position = partition(a, low, high); //划分
	if(low < high)
	{
		quickSort(a, low, position - 1);
		quickSort(a, position + 1, high);
	}
}

int main()
{
	int a[] = {4, 5, 1, 3, 2, 0, -3 ,-20, 100, 50};
	quickSort(a, 0, 10 - 1);
	int i;
	for(i = 0; i < 10; i++)
		cout << a[i] << " ";
	cout << endl;
    return 0;
}