快速排序的各种方法

#include <iostream>
#include <stack>
using namespace std;

int partition(int* arr, int left, int right)
{
	int key = arr[left];
	int i = left, j = right;
	while (1)
	{
		while ((i<j)&&(arr[j] >= key)) {
			j--;
		}
		while ((i<j)&&(arr[i] <= key)) {
			i++;
		}
		if (i < j)
			swap(arr[i], arr[j]);
		else break;
	}
	swap(arr[i], arr[left]);
	return i;
}

void quickSort1(int* arr, int left, int right)
{
	if (left<right)
	{
		int p = partition(arr, left, right);//分界点

		quickSort1(arr, left, p - 1);
		quickSort1(arr, p + 1, right);
	}
}

void quickSort2(int* arr, int left, int right)
{
	stack<int> t;
	if (left<right)
	{
		int p = partition(arr, left, right);

		if (p - 1>left)
		{
			t.push(left);
			t.push(p - 1);
		}
		if (p + 1<right)
		{
			t.push(p + 1);
			t.push(right);
		}

		while (!t.empty())
		{
			int r = t.top();
			t.pop();
			int l = t.top();
			t.pop();

			p = partition(arr, l, r);

			if (p - 1>l)
			{
				t.push(l);
				t.push(p - 1);
			}
			if (p + 1<r)
			{
				t.push(p + 1);
				t.push(r);
			}

		}
	}
}


int main()
{
	int n = 5;
	int arr[5] = { 8, 3, 6, 4, 9 };
	//int* arr;
	//cin >> n;
	//arr = new int[n];
	//for (int i = 0; i < n; i++){
	//	cin>>arr[i];
	//}
	//function(arr, 0, 4);
	stack<int> t;
	int index = arr[0];
	int i = 0;
	int j = n - 1;
	quickSort1(arr, i, j);
	
	for (int i = 0; i < n; i++){
		cout << arr[i] << " ";
	}
	cout << endl;
	return 0;
}