PTA-7-9 快速排序

代码如下：

#include<iostream>
using namespace std;
int change(int arr[], int n, int left, int right,int *count);
void sort(int arr[], int left, int right, int n,int *count);
void exchange(int arr[], int left, int right);

int main()
{
	int n, i, arr[100] = { 0 };
	int count = 3;
	cin >> n;
	for (i = 0; i < n; i++)
	{
		cin >> arr[i];
	}
	sort(arr, 0, n - 1, n,&count);
	return 0;
}

int change(int arr[],int n,int left,int right,int *count)
{
	int st, flag,i;
	flag = arr[left];
	st = left;
	while (left < right)
	{
		if (left == st)
		{
			if (arr[right] > flag)
			{
				right--;
			}
			if (arr[right] < flag)
			{
				exchange(arr, st, right);
				st = right;
				left++;
			}
		}
		if (right == st)
		{
			if (arr[left] > flag)
			{
				exchange(arr, st, left);
				st = left;
				right--;
			}
			if (arr[left] < flag)
			{
				left++;
			}
		}
		if (left == right)
		{
			arr[st] = flag;
		}
	}
	if (*count)
	{
		for (i = 0; i < n; i++)
		{
			cout << arr[i] << ' ';
		}
		if(*count>1)
			cout << endl;
		(*count)--;
	}
	return left;
}

void sort(int arr[],int left, int right,int n,int *count)
{
	if (left < right)
	{
		int flag = change(arr, n, left, right,count);
		sort(arr, left, flag - 1,n,count);
		sort(arr, flag + 1, right,n,count);
	}
}
void exchange(int arr[],int left, int right)
{
	int m;
	m = arr[left];
	arr[left] = arr[right];
	arr[right] = m;
}