可重集的排列：投机取巧的做法，利用STL的next_permutation

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

int main()  
{  
	int p[5] = {4, 1, 1, 4, 1};
	sort(p, p+5);	//排序
	do 
	{
		for (int i = 0; i < 5; i++)
		{
			printf("%d ", p[i]);
		}
		printf("\n");
	} while (next_permutation(p, p+5));
	return 0;
}