https://www.luogu.com.cn/record/163284444

样例过了。

#include<bits/stdc++.h>
using namespace std;
long long n,m,sx,sy,x[1005][1005],y[1005][1005];
int main()
{
    cin>>n>>m>>sx>>sy;
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
            cin>>x[i][j]>>y[i][j];
    cout<<sx<<" "<<sy<<endl;
    while(1)
    {
        if(x[sx][sy]==0&&y[sx][sy]==0)
            break;
        int xx=sx,yy=sy;
        sx=x[xx][yy];
        sy=y[xx][yy];
        cout<<sx<<" "<<sy<<endl;
    }
	return 0;
}