Đếm đường đi trên ma trận (GRID1) - DP

#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <cmath>
using namespace std;
const int N = 1e3, mod = 1e9 + 7;
char a[N+1][N+1];
int dp[N+1][N+1], h, w;
void read()
{
   cin >> h >> w;
   for (int i = 1; i <= h; ++ i)
   {
       for (int j = 1; j <= w; ++ j)
       {
           cin >> a[i][j];
       }
   }
}
void solve()
{
    dp[0][1] = 1;
    for (int i = 1; i <= h; ++ i)
    {
        for (int j = 1; j <= w; ++ j)
        {
            if (a[i][j] == '#')
            {
                dp[i][j] = 0;
            }
            else
            {
                dp[i][j] = (dp[i][j-1] + dp[i-1][j]) % mod;
            }
        }
    }
    cout << dp[h][w];
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    read();
    solve();
}