1690.cpp

另外一部分在nankai上面写的题目

#include <cstdio>
#include <memory>
#define max 10001
int f[max],m,n,tot,rest,sign[max],sum;
void scan()
{
	int x,y;
	memset(f,0,sizeof(f));
	memset(sign,0,sizeof(sign));
	while (m--)
	{
		scanf("%d%d",&x,&y);
		f[x]=y;sign[x]=1;
	}
}

void go(int t)
{
	int temp;
	while (f[t]!=0)
	{
		temp=t;
		t=f[t];
		f[temp]=0;sign[temp]=0;
		rest--;
	}
}

int main()
{
	int i;
	scanf("%d",&tot);
	for (i=1;i<=tot;i++)
	{
		scanf("%d%d",&n,&m);
		scan();rest=m;sum=0;
		while (rest!=0)
		{
			for (i=1;i<=max;i++)
			{
				if (sign[i]==1) go(i);
				sum++;
			}
		}
		printf("%d\n",sum);
	}
	return 1;
}