hdu--1242--bfs+优先队列

 1 #include <iostream>
 2 #include <cstring>
 3 #include <queue>
 4 using namespace std;
 5 
 6 int n , m;
 7 const int size = 210;
 8 int dir[4][2]={1,0,-1,0,0,1,0,-1}; 
 9 char maze[size][size];
10 bool vis[size][size];
11 struct data
12 {
13     int x;
14     int y;
15     int step;
16     bool operator < (const data& p )const
17     {
18         return p.step<step;
19     }
20 }st , end;
21 
22 int bfs( )
23 {
24     priority_queue<data> q;
25     data now , next;
26     int xx , yy;
27     memset( vis , false , sizeof(vis) );
28     while( !q.empty() )
29         q.pop();
30     q.push( st );
31     vis[ st.x ][ st.y ] = true;
32     while( !q.empty() )
33     {
34         now = q.top();
35         q.pop();
36         if( now.x == end.x && now.y == end.y )
37             return now.step;
38         for( int i = 0 ; i<4 ; i++ )
39         {
40             xx = now.x + dir[i][0];
41             yy = now.y + dir[i][1];
42             if( xx>=0 && xx<n && yy>=0 && yy<m && maze[xx][yy]!=‘#‘ && !vis[xx][yy] )
43             {
44                 if( maze[xx][yy] == ‘x‘ )
45                     next.step = now.step + 2;
46                 else
47                     next.step = now.step + 1;
48                 next.x = xx;
49                 next.y = yy;
50                 vis[xx][yy] = true;
51                 q.push( next );
52             }
53         }
54     }
55     return -1;
56 }
57 
58 int main()
59 {
60     int ans;
61     while( cin >> n >> m )
62     {
63         for( int i = 0 ; i<n ; i++ )
64         {
65             for( int j = 0 ; j<m ; j++ )
66             {
67                 cin >> maze[i][j];
68                 if( maze[i][j] == ‘a‘ )
69                 {
70                     st.x = i;
71                     st.y = j;
72                     st.step = 0;    
73                 }
74                 else if( maze[i][j] == ‘r‘ )
75                 {
76                     end.x = i;
77                     end.y = j;
78                 }
79             }
80         }
81         ans = bfs();
82         if( -1 == ans )
83             cout << "Poor ANGEL has to stay in the prison all his life." << endl;            
84         else
85             cout << ans << endl;
86     }
87     return 0;
88 }