快速排序

[c++]代码库

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

const int size = 1000;


int partition ( int a[], int low, int high )
{
	//选择第一个a[low]作为划分的临界值
	while ( low < high )
	{
		while ( low < high && a[low] <= a[high] ) high--;
		swap ( a[low], a[high] );
		while ( low < high && a[low] <= a[high] ) low++;
		swap ( a[low], a[high] );
	}
	return low;
}

void Qsort ( int a[], int low, int high )
{
	if ( low > high ) return;
	int p = partition ( a, low, high );
	Qsort ( a, low, p-1 );
	Qsort ( a, p+1, high );
}

int main()
{
	int N, arr[size];
	int i;
	while ( cin >> N )
	{
		for ( i = 0; i < N; ++i )
			cin >> arr[i];

		Qsort ( arr, 0, N-1 );

		for ( i = 0; i < N-1; ++i )
			cout << arr[i] << " ";
		cout << arr[i] << endl;

	}
	return 0;
}