【CodeForces 611C】New Year and Domino

#include <stdio.h>
#include <algorithm>
#define F(a,b,c) for(int a=b;a<=c;a++)
#define N 505
using namespace std;
int h,w,a[N][N],b[N][N],q,ans;
int r1,c1,r2,c2;
char ch;
int main()
{
    scanf("%d%d",&h,&w);
    F(i,1,h)F(j,1,w)
    {
        scanf(" %c",&ch);
        if (ch == '.')
            a[i][j]=1;
    }
    F(i,1,h)F(j,1,w)
    {
        b[i][j] = b[i][j-1] + b[i-1][j] - b[i-1][j-1];
        if (a[i][j])
            b[i][j] += a[i][j-1] + a[i-1][j];
    }
    scanf("%d",&q);
    F(i,1,q)
    {
        scanf("%d%d%d%d",&r1,&c1,&r2,&c2);
        ans = b[r2][c2] - b[r2][c1-1] - b[r1-1][c2] + b[r1-1][c1-1];
        F(j,r1,r2)
        if (a[j][c1] && a[j][c1-1])
            ans--;

        F(j,c1,c2)
        if (a[r1][j] && a[r1-1][j])
            ans--;

        printf("%d\n",ans);
    }
    return 0;
}