简单模拟 

#include<iostream>
#include<cstring>
using namespace std;

const int N = 20;
char map[N][N];
bool st[N][N];
int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};

int main()
{
    int n,m;
    while(cin>>n>>m)
    {
        memset(map,'*',sizeof map);
        memset(st, 0, sizeof st);
        char dir;
        int x, y;
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=m;j++)
            {
                cin>>map[i][j];
                if(map[i][j]!='.' && map[i][j]!='*') 
                {
                    dir = map[i][j];
                    x = i, y = j;
                }
            }
        }
        int idx;
        if(dir=='U') idx = 0;
        else if(dir=='D') idx = 2;
        else if(dir=='L') idx = 3;
        else idx = 1;
        
        int cnt=1;
        st[x][y] = true;
        while(1)
        {
            int nx = x + dx[idx], ny = y + dy[idx]...