【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。

 #include <iostream>
 #include <queue>
 #include <cstring>
 #include <cstdio>
 using namespace std;

 typedef struct node_st {
     int x, y, t;
     int key;
     node_st() {}
     node_st(int xx, int yy, int tt, int kk) {
         x = xx; y = yy; t = tt; key = kk;
     }
 } node_st;

 char map[][];
 char visit[<<][][];
 int direct[][] = {{-,},{,},{,-},{,}};
 int n, m, time;

 int bfs(int bx, int by) {
     int x, y, key, t;
     int i, tmp;
     queue<node_st> que;
     node_st node;

     memset(visit, , sizeof(visit));
     visit[bx][by][] = ;
     que.push(node_st(bx,by,,));

     while ( !que.empty() ) {
         node = que.front();
         if (node.t >= time)
             return -;
         if (map[node.x][node.y] == '^')
             return node.t;
         que.pop();
         t = node.t + ;
         for (i=; i<; ++i) {
             x = node.x + direct[i][];
             y = node.y + direct[i][];
             if (x< || x>=n || y< || y>=m)
                 continue;
             if (map[x][y]>='a' && map[x][y]<='j')
                 key = node.key | (<<(map[x][y]-'a'));
             else
                 key = node.key;
             if (visit[key][x][y] || map[x][y]=='*')
                 continue;
             if (map[x][y]>='A' && map[x][y]<='J') {
                 tmp = (<<(map[x][y]-'A')) & key;
                 if ( !tmp )
                     continue;
             }
             que.push(node_st(x,y,t,key));
             visit[key][x][y] = ;
         }
     }

     return -;
 }

 int main() {
     int bx, by;
     int i, j;

     while (scanf("%d %d %d", &n, &m, &time) != EOF) {
         for (i=; i<n; ++i) {
             scanf("%s", map[i]);
             for (j=; j<m; ++j) {
                 if (map[i][j] == '@') {
                     bx = i;
                     by = j;
                 }
             }
         }
         i = bfs(bx, by);
         printf("%d\n", i);
     }

     return ;
 }