1 #include<cstdio>
2 #include<cstring>
3 int sx[4]={0,1,0,-1};
4 int sy[4]={1,0,-1,0};
5 int g[10][10];
6 int x1,y1,x2,y2;
7 int step;
8 int n,m,t;
9 void dfs(int x,int y,int c_step)
10 {
11
12 if(x==x2&&y==y2&&c_step==t)
13 {
14
15 step=1;return;
16 }
17 if((x>x2?x-x2:x2-x)+(y>y2?y-y2:y2-y)+c_step>t)//小剪
18 {
19 return;
20 }
21 int i;
22 for(i=0;i<4;i++)
23 {
24 int xx,yy;
25 xx=x+sx[i];
26 yy=y+sy[i];
27 if(xx>=1&&xx<=n&&yy>=1&&yy<=m&&g[xx][yy]==0&&c_step+1<=t)
28 {
29 g[xx][yy]=1;
30 dfs(xx,yy,c_step+1);
31 if(step==1)//强力缩短时间
32 return;
33 g[xx][yy]=0;
34 }
35 }
36
37 }
38 int main()
39 {
40 int i,j,sum;
41 char c;
42 while(scanf("%d %d %d",&n,&m,&t)!=EOF)
43 {
44 if(!n&&!m&&!t)break;
45 step=0;
46 sum=0;
47 getchar();
48 for(i=1;i<=n;i++)
49 {
50 for(j=1;j<=m;j++)
51 {
52 c=getchar();
53 if(c=='S')
54 x1=i,y1=j;
55 else if(c=='D')
56 x2=i,y2=j,g[i][j]=0;
57 else if(c=='X')
58 g[i][j]=1;
59 else if(c=='.')
60 g[i][j]=0,sum++;
61 }
62 getchar();
63 }
64 if(sum+1<t||(t+x1+y1+x2+y2)%2==1)//奇偶性判别与可达性判别
65 printf("NO\n");
66 else
67 {
68 g[x1][y1]=1;
69 dfs(x1,y1,0);
70 if(step)
71 printf("YES\n");
72 else
73 printf("NO\n");
74 }
75 }
76 return 0;
77 }
