intro-dp-exmp2-bu.cpp

char A[MAX_N][MAX_M]; // assume the board's data is in A[1..n][1..m]
int dp[MAX_N][MAX_M]; // set everything to 0 (so dp[0][0..m] and dp[0..n][0] will be 0)

for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= m; ++j) {
        if (A[i][j] == '#')
            dp[i][j] = 0;
        else if (i == 1 && j == 1)
            dp[i][j] = 1;
        else
            dp[i][j] = dp[i-1][j] + dp[i][j-1];
    }
}

// according to the above example:
// cout << dp[5][4] << endl;
// result = 3