1 #include <cstdio> 
 2 #include <iostream>
 3 #include <cstring>
 4 using namespace std;
 5 int T,n,m,head,tail,px,py,qx,qy,state[20010][5],dx[4]={0,0,1,-1},dy[4]={1,-1,0,0};
 6 bool vis[110][110];
 7 char a[110][110];
 8 double l;
 9 bool pd(int x,int y)
10 {
11     if (x<=0||y<=0||x>n||y>m||vis[x][y]||a[x][y]==‘#‘) return false;
12     return true;
13 }
14 void bfs()
15 {
16     head=0,tail=1,state[1][1]=px,state[1][2]=py,vis[px][py]=1;
17     while (head<tail)
18     {
19         head++;
20         for (int i=0;i<4;i++)
21         {
22             int x=state[head][1]+dx[i],y=state[head][2]+dy[i];
23             if (pd(x,y))
24             {
25                 tail++,state[tail][1]=x,state[tail][2]=y,vis[x][y]=1;
26                 if (x==state[head][1]) state[tail][3]=state[head][3]+1,state[tail][4]=state[head][4];
27                 else state[tail][3]=state[head][3],state[tail][4]=state[head][4]+1;
28                 if (x==qx&&y==qy&&l>=state[tail][3])
29                 {
30                     printf("%.5lf\n",(l-state[tail][3])/state[tail][4]);
31                     return;
32                 }
33                 if (x==qx&&y==qy) tail--,vis[qx][qy]=0;
34             }
35         }
36     }
37 }
38 int main()
39 {
40     freopen("maze.in","r",stdin),freopen("maze.out","w",stdout);
41     scanf("%d",&T);
42     while (T--)
43     {
44         memset(vis,0,sizeof(vis)),memset(state,0,sizeof(state));
45         scanf("%lf%d%d",&l,&n,&m);
46         for (int i=1;i<=n;i++)
47         {
48             scanf("\n");
49             for (int j=1;j<=m;j++)
50             {
51                 a[i][j]=getchar();
52                 if (a[i][j]==‘S‘) px=i,py=j;
53                 if (a[i][j]==‘E‘) qx=i,qy=j;
54             }
55         }
56         bfs();
57     }
58 }