题解 | #牛牛的金币#

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int pos,oddX=0,evenY=0,count=0;
    while(cin>>pos)
    {
        if(!(count%2))
            oddX+=pow(-1,count/2)*pos;
        else
            evenY+=pow(-1,count/2)*pos;
        count++;
        if(count>3)
            break;
    }
    if(abs(oddX)+abs(evenY)==1)
    {
        switch(oddX)
        {
            case (-1):cout<<"r"<<endl;break;
            case 1:cout<<"l"<<endl;break;
            case 0:
            {
                switch(evenY)
                {
                    case (-1):cout<<"u"<<endl;break;
                    case 1:cout<<"d"<<endl;break;
                }
                break;
            }
            default:break;
        }
    }
    return 0;
}