#include<iostream>
using namespace std;

int main(){
	int *ad,*r,n,k,c=0,f,tt=0,*tf;
	int t,x=1,i,p,q=0;
	cin>>n>>k;
	ad=new int[n+1];
	r=new int [n+1];
	memset(ad,0,4*n+4);
	memset(r,0,4*n+4);
	for(t=0;t<k;t++ ){
		cin>>f;
		tt=tt+f;
		for(p=0;p<f;p++){
			q++;
			cin>>ad[q];
			r[ad[q]]=1;
		}}
	tf=new int [tt+1];
	memset(tf,1,4*tt+4);
	for (i=1;i<=tt;i++){
		x=i;
		while(!r[x]&&x<=tt){
			tf[x]=0;
			r[ad[x]]=0;
			r[x]=1;
			cout<<ad[x]<<" "<<x<<endl;
			x=ad[x];
		}

		
	}

	for (i=1;i<=tt;i++){
		
		if (tf[i]&&ad[i]!=i&&tf[ad[i]]){
			x=c=i;
			r[c]=0;
			cout<<i<<" "<<n<<endl;
			while(!r[x]&&x<=tt){		
		r[ad[x]]=0;
		tf[x]=0;
		r[x]=1;
		cout<<ad[x]<<" "<<x<<endl;
		x=ad[x];
		if(ad[x]==c)
			break;

	}
	cout<<n<<" "<<x<<endl;
		
		}
}

	
return 0;

}

• 测试数据 (31) yzq110abc 2010-03-07 19:15:34