Codeforces Round #516 (Div. 2, by Moscow Team Olympiad) D. Labyrinth

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 #define ll long long
 4 #define minv 1e-6
 5 #define inf 1e9
 6 #define pi 3.1415926536
 7 #define nl 2.7182818284
 8 const ll mod=1e9+7;//998244353
 9 const int maxn=(2e3+10)*(2e3+10);
10 
11 int q[maxn],step[maxn];
12 char s[maxn];
13 int n,m,bx,by,gl,gr,head,tail,phead,i,sum=0,l,r,d;
14 
15 void add(int d,int pos,int k)
16 {
17     tail++;
18     q[tail]=d;
19     s[d]=‘*‘;
20     step[tail]=step[pos]+k;
21     r=(d%m-by+step[tail])/2;
22     l=step[tail]-r;
23     if (l<=gl && r<=gr)
24         sum++;
25 }
26 
27 int main()
28 {
29     scanf("%d%d",&n,&m);
30     scanf("%d%d",&bx,&by);
31     scanf("%d%d",&gl,&gr);
32     bx--,by--,sum++;
33     q[1]=bx*m+by;
34     for (i=1;i<=n;i++)
35         scanf("%s",s+(i-1)*m);
36     s[q[1]]=‘*‘;
37     head=1,tail=1;
38     while (head<=tail)
39     {
40         phead=head;
41         while (head<=tail)
42         {
43             d=q[head]-m;
44             if (d>=0 && s[d]==‘.‘)
45                 add(d,head,0);
46             d=q[head]+m;
47             if (d<n*m && s[d]==‘.‘)
48                 add(d,head,0);
49             head++;
50         }
51         //[phead,tail] (head-1)
52         while (phead<head)
53         {
54             d=q[phead]-1;
55             if (d%m!=m-1 && s[d]==‘.‘)
56                 add(d,phead,1);
57             d=q[phead]+1;
58             if (d%m!=0 && s[d]==‘.‘)
59                 add(d,phead,1);
60             phead++;
61         }
62     }
63     printf("%d",sum);
64     return 0;
65 }