hdu1242BFS 

 1 #include<iostream>
 2 #include<queue>
 3 #include<cstdio>
 4 using namespace std;
 5 
 6 char mp[201][201];
 7 int m,n,dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}};
 8 
 9 struct point
10 {
11     int x,y,step;
12     friend bool operator <(point t1,point t2)
13     {
14         return t1.step>t2.step;
15     }
16 };
17 
18 void bfs(point S)
19 {
20     int i;
21     point t,tt;
22     priority_queue<point>Q;
23     Q.push(S);
24     while(!Q.empty())
25     {
26         t=Q.top();
27         Q.pop();
28         for(i=0;i<4;i++)
29         {
30             tt.x=t.x+dir[i][0];tt.y=t.y+dir[i][1];  tt.step=t.step+1;
31             if(tt.x<1||tt.x>m||tt.y<1||tt.y>n||mp[tt.x][tt.y]=='#') continue;
32             if(mp[tt.x][tt.y]=='r') {printf("%d\n",tt.step);return;}
33             if(mp[tt.x][tt.y]=='x') tt.step++;
34 
35             mp[tt.x][tt.y]='#';
36             Q.push(tt);
37         }
38     }
39     printf("Poor ANGEL has to stay in the prison all his life.\n");
40     return;
41 }
42 
43 int main()
44 {
45     int i,j;
46     point S;
47 
48     while(scanf("%d%d",&m,&n)!=EOF)
49     {
50         getchar();
51         for(i=1;i<=m;i++)
52         {
53             for(j=1;j<=n;j++)
54             {
55                 scanf("%c",&mp[i][j]);
56                 if(mp[i][j]=='a')
57                 {
58                     S.x=i;
59                     S.y=j;
60                     S.step=0;
61                 }
62             }
63             getchar();
64         }
65         bfs(S);
66     }
67     return 0;
68 }
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posted @ 2014-08-08 23:43  tt_tt--->  阅读(82)  评论(0)    收藏  举报