POJ 3984

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <cstdlib>
 4 #include <cctype>
 5 #include <cmath>
 6 #include <time.h>
 7 #include <string>
 8 #include <map>
 9 #include <stack>
10 #include <set>
11 #include <queue>
12 #include <vector>
13 #include <algorithm>
14 #include <iostream>
15 using namespace std;
16 typedef long long ll;
17 #define PI acos( -1.0 )
18 typedef pair<int, int> P;
19 const double E = 1e-8;
20 const int NO = 100 + 5;
21 int a[10][10], dx[10][10], dy[10][10];
22 int mark[10][10];
23 int dir[][2] = { {-1,0}, {1,0}, {0,-1}, {0,1} };
24 
25 void output( int x, int y )
26 {
27     if( x == 0 && y == 0 )
28     {
29         printf( "(0, 0)\n" );
30         return;
31     }
32     output( dx[x][y], dy[x][y] );
33     printf( "(%d, %d)\n", x, y );
34 }
35 
36 void bfs()
37 {
38     queue <P> q;
39     memset( mark, 0, sizeof( mark ) );
40     memset( dx, 0, sizeof( dx ) );
41     memset( dy, 0, sizeof( dy ) );
42     q.push( P( 0, 0 ) );
43     dx[0][0] = dy[0][0] = -1;
44     while( !q.empty() )
45     {
46         P t = q.front(); q.pop();
47         if( t.first == 4 && t.second == 4 )
48         {
49             output( 4, 4 );
50             return;
51         }
52         for( int i = 0; i < 5; ++i )
53         {
54             int xx = dir[i][0] + t.first;
55             int yy = dir[i][1] + t.second;
56             if( xx >= 0 && xx < 5 && yy >= 0 && yy < 5 && !mark[xx][yy] && a[xx][yy] == 0 )
57             {
58                 mark[xx][yy] = 1;
59                 dx[xx][yy] = t.first;
60                 dy[xx][yy] = t.second;
61                 q.push( P( xx, yy ) );
62             }
63         }
64     }
65 }
66 
67 int main()
68 {
69     for( int i = 0; i < 5; ++i )
70         for( int j = 0; j < 5;++j )
71             scanf( "%d", &a[i][j] );
72     bfs();
73     return 0;
74 }