【HDOJ】1429 胜利大逃亡(续)

BFS+状态压缩，做了很多状态压缩了。今晚把八数码问题给搞定了。

 1 #include <iostream>

 2 #include <queue>

 3 #include <cstring>

 4 #include <cstdio>

 5 using namespace std;

 6

 7 typedef struct node_st {

 8     int x, y, t;

 9     int key;

10     node_st() {}

11     node_st(int xx, int yy, int tt, int kk) {

12         x = xx; y = yy; t = tt; key = kk;

13     }

14 } node_st;

15

16 char map[25][25];

17 char visit[1<<10][25][25];

18 int direct[4][2] = {{-1,0},{1,0},{0,-1},{0,1}};

19 int n, m, time;

20

21 int bfs(int bx, int by) {

22     int x, y, key, t;

23     int i, tmp;

24     queue<node_st> que;

25     node_st node;

26

27     memset(visit, 0, sizeof(visit));

28     visit[bx][by][0] = 1;

29     que.push(node_st(bx,by,0,0));

30

31     while ( !que.empty() ) {

32         node = que.front();

33         if (node.t >= time)

34             return -1;

35         if (map[node.x][node.y] == ‘^‘)

36             return node.t;

37         que.pop();

38         t = node.t + 1;

39         for (i=0; i<4; ++i) {

40             x = node.x + direct[i][0];

41             y = node.y + direct[i][1];

42             if (x<0 || x>=n || y<0 || y>=m)

43                 continue;

44             if (map[x][y]>=‘a‘ && map[x][y]<=‘j‘)

45                 key = node.key | (1<<(map[x][y]-‘a‘));

46             else

47                 key = node.key;

48             if (visit[key][x][y] || map[x][y]==‘*‘)

49                 continue;

50             if (map[x][y]>=‘A‘ && map[x][y]<=‘J‘) {

51                 tmp = (1<<(map[x][y]-‘A‘)) & key;

52                 if ( !tmp )

53                     continue;

54             }

55             que.push(node_st(x,y,t,key));

56             visit[key][x][y] = 1;

57         }

58     }

59

60     return -1;

61 }

62

63 int main() {

64     int bx, by;

65     int i, j;

66

67     while (scanf("%d %d %d", &n, &m, &time) != EOF) {

68         for (i=0; i<n; ++i) {

69             scanf("%s", map[i]);

70             for (j=0; j<m; ++j) {

71                 if (map[i][j] == ‘@‘) {

72                     bx = i;

73                     by = j;

74                 }

75             }

76         }

77         i = bfs(bx, by);

78         printf("%d\n", i);

79     }

80

81     return 0;

82 }