1321.cpp

这些是我到目前在PKU上做出的题目

#include <iostream.h>

char o;
bool a[9][9],r[9];
int tot,i,j,n,m;

void play(int fl,int now)
{
	int i;
	if (fl>n)
	{
		if (now==m)
			tot++;
	}
	else
	{
		play(fl+1,now);
		if (now<m)
			for (i=1;i<=n;i++)
				if (a[fl][i] && r[i])
				{
					r[i]=0;
					play(fl+1,now+1);
					r[i]=1;
				}
	}
}

int main()
{
	cin>>n>>m;
	while (n!=-1)
	{
		for (i=1;i<=n;i++)
			for (j=1;j<=n;j++)
			{
				cin>>o;
				if (o=='#')
					a[i][j]=1;
				else
					a[i][j]=0;
			}
		tot=0;
		for (i=1;i<=n;i++)
			r[i]=1;
		play(1,0);
		cout<<tot<<"\n";
		cin>>n>>m;
	}
	return 0;
}