CSES - Shared codeLink to this code:
https://cses.fi/paste/1298e773dc80a66513be46/
/** これを翻訳している間、あなたはあなたの人生のいくつかの貴重な瞬間を無駄にしました **/
#include<bits/stdc++.h>
using namespace std;
#define rep(i,x,y) for(int i=x;i<y;i++)
#define repr(i,x,y) for(int i=x;i>=y;i--)
#define pb push_back
#define ff first
#define ss second
#define sz(x) ((int)x.size())
#define all(x) begin(x), end(x)
#define memo(x,y) memset((x),(y),sizeof((x)))
using pii = pair<int,int>;
using vi = vector<int>;
using vii = vector<pair<int,int>>;
constexpr int mod = 1e9 + 7 , N = 2e5 + 5;
constexpr long long inf = 1e18;
constexpr long double eps = 1e-6;
string s;
int vis[7][7];
int cnt=0;
bool ok(int x, int y) { return x >= 0 && y >= 0 && x < 7 && y < 7; }
void go(int x,int y,int idx){
if( x==0&&y==6){
if(idx==48)cnt++;
return;
}
if(ok(x-1,y)&&vis[x-1][y])
if(ok(x+1,y)&&vis[x+1][y])
if(ok(x,y-1)&&!vis[x][y-1])
if(ok(x,y+1)&&!vis[x][y+1])
return;
if(ok(x,y-1)&&vis[x][y-1])
if(ok(x,y+1)&&vis[x][y+1])
if(ok(x-1,y)&&!vis[x-1][y])
if(ok(x+1,y)&&!vis[x+1][y])
return;
if(x==6||x==0)
if(ok(x,y-1)&&!vis[x][y-1])
if(ok(x,y+1)&&!vis[x][y+1])
return;
if(y==6||y==0)
if(ok(x-1,y)&&!vis[x-1][y])
if(ok(x+1,y)&&!vis[x+1][y])
return;
vis[x][y]=1;
if(s[idx]=='?' || s[idx]=='R'){
if(ok(x+1,y)){
if(vis[x+1][y]==0)
go(x+1,y,idx+1);
}
}
if(s[idx]=='?' || s[idx]=='D'){
if(ok(x,y+1)){
if(vis[x][y+1]==0)
go(x,y+1,idx+1);
}
}
if(s[idx]=='?' || s[idx]=='U'){
if(ok(x,y-1)){
if(vis[x][y-1]==0)
go(x,y-1,idx+1);
}
}
if(s[idx]=='?' || s[idx]=='L'){
if(ok(x-1,y)){
if(vis[x-1][y]==0)
go(x-1,y,idx+1);
}
}
vis[x][y]=0;
}
void Onigiri()
{
cin>>s;
go(0,0,0);
cout<<cnt;
}
signed main()
{
ios_base::sync_with_stdio(false);cin.tie(NULL);
//cout.precision(10);cout<<fixed;
#ifdef Zoro
freopen("/home/pritish/Competitive/in", "r", stdin);
freopen("/home/pritish/Competitive/out", "w", stdout);
#endif
int t=1;
//cin>>t;
while(t--)
{Onigiri();cout<<"\n";}
cerr<<"\n"<<(float)clock()/CLOCKS_PER_SEC*1000<<" ms"<<endl;
return 0;
}