1 #include <iostream>
 2 #include <cstdio>
 3 using namespace std;
 4 
 5 const int dx[4] = { 0, 1, 0, -1 }, dy[4] = { 1, 0, -1, 0 };
 6 
 7 char a[505][505];
 8 int r, c, sx, sy, ex, ey;
 9 
10 bool dfs(int x, int y)
11 {
12     if (x == ex && y == ey && a[x][y] == ‘X‘)
13     {
14         return true;
15     }
16     a[x][y] = ‘X‘;
17     for (int i = 0; i < 4; i++)
18     {
19         int nx = x + dx[i];
20         int ny = y + dy[i];
21         if (nx >= 1 && nx <= r && ny >= 1 && ny <= c && 
22             (a[nx][ny] == ‘.‘ || (nx == ex && ny == ey)))
23         {
24             if (dfs(nx, ny))
25                 return true;
26         }
27     }
28     return false;
29 }
30 
31 int main()
32 {
33     cin >> r >> c;
34     for (int i = 1; i <= r; i++)
35     {
36         for (int j = 1; j <= c; j++)
37         {
38             cin >> a[i][j];
39         }
40     }
41     cin >> sx >> sy >> ex >> ey;
42     a[sx][sy] = ‘.‘;
43     if (dfs(sx, sy))
44         puts("YES");
45     else
46         puts("NO");
47     return 0;
48 }