RT，调了将近1小时了，还是WA+RE

#include <bits/stdc++.h>
using namespace std;
int n,m,vis[51][51][51][51];
int dx[5]={0,1,-1,0,0};//Right Left Down Up
int dy[5]={0,0,0,1,-1};
char ch[51][51];
bool dfs(int y,int x,int me,int d)
{
    y=(y+n)%n;
    x=(x+m)%m;
    if(vis[y][x][me][d])
        return 0;
    vis[y][x][me][d]=1;
    if(ch[y][x]=='<')
        d=2;
    else if(ch[y][x]=='>')
        d=1;
    else if(ch[y][x]=='^')
        d=4;
    else if(ch[y][x]=='v')
        d=3;
    else if(ch[y][x]=='_')
    {
        if(!me)
            d=1;
        else
            d=2;
    }
    else if(ch[y][x]=='|')
    {
        if(!me)
            d=3;
        else
            d=4;
    }
    else if(ch[y][x]=='?')
        for(int i=1;i<4;i++)
            if(dfs(y+dy[i],x+dx[i],me,i))
                return 1;
    else if(ch[y][x]=='@')
        return 1;
    else if(ch[y][x]=='+')
        me=(me+1)%16;
    else if(ch[y][x]=='-')
        me=(me+15)%16;
    else
        me=ch[y][x]-'0';
}
int main()
{
    ios::sync_with_stdio(0);
    cin>>n>>m;
    for(int i=0;i<n;i++)
            cin>>ch[i];
    if(dfs(0,0,0,1))
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl; 
    return 0;
}