BZOJ 1054 [HAOI2008]移动玩具

 1 #include <queue>
 2 #include <cstdio>
 3 
 4 using namespace std;
 5 
 6 unsigned int Start, End;
 7 bool M[4][4];
 8 
 9 const int dx[] = {+0, +0, +1, -1};
10 const int dy[] = {+1, -1, +0, +0};
11 
12 void init()
13 {
14     char Map[4][4];
15     unsigned int Temp;
16     for (int i = 0;i != 4;++i)
17     {
18         scanf("%s", Map + i);
19         Temp = 0;
20         for (int j = 0;j != 4;++j)
21             (Temp <<= 1) += Map[i][j] - ‘0‘;
22         Start += (Temp << (i << 2));
23     }
24     for (int i = 0;i != 4;++i)
25     {
26         scanf("%s", Map + i);
27         Temp = 0;
28         for (int j = 0;j != 4;++j)
29             (Temp <<= 1) += Map[i][j] - ‘0‘;
30         End += (Temp << (i << 2));
31     }
32 }
33 
34 int Dist[100050];
35 
36 void BFS()
37 {
38     queue<unsigned int> Q;
39     Q.push(Start);
40     unsigned int Top, Temp, Go;
41     int x, y;
42     Dist[Start] = 1;
43     while (Q.size())
44     {
45         Top = Q.front();
46         Q.pop();
47         for (int i = 0;i != 4;++i)
48             for (int j = 0;j != 4;++j)
49                 M[i][j] = (Top & (1 << (i * 4 + (3 - j))));
50         for (int i = 0;i != 4;++i)
51             for (int j = 0;j != 4;++j)
52                 if (M[i][j])
53                     for (int k = 0;k != 4;++k)
54                     {
55                         x = i + dx[k], y = j + dy[k];
56                         if (x >= 0 && x < 4 && y >= 0 && y < 4)
57                             if (!M[x][y])
58                             {
59                                 swap(M[i][j], M[x][y]);
60                                 Go = 0;
61                                 for (int i = 0;i != 4;++i)
62                                 {
63                                     Temp = 0;
64                                     for (int j = 0;j != 4;++j)
65                                         (Temp <<= 1) += M[i][j];
66                                     Go += (Temp << (i << 2));
67                                 }
68                                 if (!Dist[Go])
69                                 {
70                                     Dist[Go] = Dist[Top] + 1;
71                                     Q.push(Go);
72                                 }
73                                 swap(M[i][j], M[x][y]);
74                             }
75                     }
76         if (Dist[End])
77             break;
78     }
79 }
80 
81 int main()
82 {
83     init();
84     BFS();
85     printf("%u", Dist[End] - 1);
86     return 0;
87 }