【HDOJ】3309 Roll The Cube

BFS，考虑一球进洞仅一球滚动以及两球重叠的情况即可。

 /* 3309 */
 #include <iostream>
 #include <queue>
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 using namespace std;

 #define MAXN 25

 typedef struct {
     int x[], y[];
     bool in[];
     int t;
 } node_t;

 int n, m;
 node_t beg;
 bool visit[MAXN][MAXN][MAXN][MAXN];
 char map[MAXN][MAXN];
 int dir[][] = {
     -,,,,,-,,
 };

 inline bool check(int x, int y) {
     return x< || x>=n || y< || y>=m;
 }

 int bfs() {
     int i, j, k;
     node_t d, nd;
     queue<node_t> Q;

     memset(visit, false, sizeof(visit));
     visit[beg.x[]][beg.y[]][beg.x[]][beg.y[]] = true;
     Q.push(beg);

     while (!Q.empty()) {
         nd = Q.front();
         Q.pop();
         if (!nd.in[]) {
             if (nd.in[] == false) {
                 if (map[nd.x[]][nd.y[]] == 'H')
                     nd.in[] = true;
             }
             if (nd.in[]) {
                 if (map[nd.x[]][nd.y[]]=='H' && (nd.x[]!=nd.x[] || nd.y[]!=nd.y[]))
                     nd.in[] = true;
             } else {
                 if (map[nd.x[]][nd.y[]]=='H') {
                     nd.in[] = true;
                 }
             }
         } else {
             if (!nd.in[]) {
                 if (map[nd.x[]][nd.y[]]=='H' && (nd.x[]!=nd.x[] || nd.y[]!=nd.y[]))
                     nd.in[] = true;
             }
         }
         if (nd.in[] && nd.in[])
             return nd.t;
         ++nd.t;
         for (i=; i<; ++i) {
             d = nd;
             if (nd.in[] == false) {
                 d.x[] += dir[i][];
                 d.y[] += dir[i][];
                 if (check(d.x[], d.y[]))
                     continue;
                 if (map[d.x[]][d.y[]] == '*') {
                     d.x[] = nd.x[];
                     d.y[] = nd.y[];
                 }
             }
             if (nd.in[] == false) {
                 d.x[] += dir[i][];
                 d.y[] += dir[i][];
                 if (check(d.x[], d.y[]))
                     continue;
                 if (map[d.x[]][d.y[]] == '*') {
                     d.x[] = nd.x[];
                     d.y[] = nd.y[];
                 }
             }
             if (d.in[]==false && d.in[]==false) {
                 if (d.x[]==d.x[] && d.y[]==d.y[])
                     continue;
             }
             if (visit[d.x[]][d.y[]][d.x[]][d.y[]])
                 continue;
             visit[d.x[]][d.y[]][d.x[]][d.y[]] = true;
             Q.push(d);
         }
     }

     return -;
 }

 int main() {
     int t;
     int i, j, k;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     scanf("%d", &t);
     beg.in[] = beg.in[] = false;
     beg.t = ;
     while (t--) {
         scanf("%d %d", &n, &m);
         k = ;
         for (i=; i<n; ++i) {
             scanf("%s", map[i]);
             for (j=; j<m; ++j) {
                 if (map[i][j] == 'B') {
                     beg.x[k] = i;
                     beg.y[k] = j;
                     ++k;
                 }
             }
         }
         k = bfs();
         if (k < )
             puts("Sorry , sir , my poor program fails to get an answer.");
         else
             printf("%d\n", k);
     }

     return ;
 }