HDU 1010 Tempter of the Bone(DFS)

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 int n,m,t;
 4 int doorX,doorY;
 5 char ca[10][10];
 6 int to[4][2] = {{0,-1},{0,1},{-1,0},{1,0}};
 7 int dfs(int x,int y,int cnt)
 8 {
 9     if(x>n||y>m||x<=0||y<=0)return 0;
10     if(cnt==t&&x==doorX&&y==doorY)
11         return 1;
12     int tem=t-cnt-abs(x-doorX)-abs(y-doorY);
13     if(tem<0 || tem&1 )return 0;
14     for(int i=0; i<4; i++)
15     {
16         if(ca[x+to[i][0]][y+to[i][1]]!=‘X‘)
17         {
18             ca[x+to[i][0]][y+to[i][1]]=‘X‘;
19             if(dfs(x+to[i][0],y+to[i][1],cnt+1))return 1;
20             ca[x+to[i][0]][y+to[i][1]]=‘.‘;
21         }
22     }
23     return 0;
24 }
25 int main()
26 {
27     while(scanf("%d%d%d",&n,&m,&t)!=EOF&&n+m+t)
28     {
29         int i,j,wall=0,stratX,stratY;
30         getchar();
31         for(i=1; i<=n; i++)
32         {
33             for(j=1; j<=m; j++)
34             {
35                 scanf("%c",&ca[i][j]);
36                 if(ca[i][j]==‘S‘)
37                     stratX=i,stratY=j;
38                 else if(ca[i][j]==‘X‘)
39                     wall++;
40                 else if(ca[i][j]==‘D‘)
41                     doorX=i,doorY=j;
42             }
43             getchar();
44         }
45         if(n*m-wall<=t)
46         {
47             printf("NO\n");
48             continue;
49         }
50         ca[stratX][stratY]=‘X‘;
51         if(dfs(stratX,stratY,0))
52             printf("YES\n");
53         else
54             printf("NO\n");
55     }
56     return 0;
57 }