CSES – Grid Paths

#include<bits/stdc++.h>
#define int long long
#define pii pair<int,int>
#define f first
#define s second
#define fastio ios_base::sync_with_stdio(0);cin.tie(0)
using namespace std;
//declare
const int maxn = 1005;
const int mod = 1e9+7;
int n,dp[maxn][maxn];
char maze[maxn][maxn];
//
signed main(){
    fastio;
    cin>>n;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            cin>>maze[i][j];
        }
    }
    if(maze[1][1] == '*') return cout<<0<<"\n", 0;
    dp[1][1] = 1;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(i == 1 && j == 1) continue;
            if(maze[i][j] == '*') continue;
            dp[i][j] = dp[i-1][j] + dp[i][j-1];
            dp[i][j] %= mod;
        }
    }
    cout<<dp[n][n]<<"\n";
    return 0;
}