BFS HDOJ 1728 逃离迷宫

题目传送门

 /*
     BFS：三维BFS，加上方向。用dp[x][y][d]记录当前需要的最少转向数
 */
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 #include <queue>
 #include <cmath>
 using namespace std;

 const int MAXN = 1e2 + ;
 const int INF = 0x3f3f3f3f;
 struct P
 {
     int x, y, z;
 }now, to;
 char maze[MAXN][MAXN];
 int dp[MAXN][MAXN][];
 bool inq[MAXN][MAXN][];
 int dx[] = {-, , , };
 int dy[] = {, , -, };
 int k, x1, y1, x2, y2;
 int n, m;

 bool check(int x, int y)
 {
     if (x >=  && x <= n && y >=  && y <= m)    return true;
     else    return false;
 }

 bool BFS(void)
 {
     memset (dp, , sizeof (dp));
     memset (inq, false, sizeof (inq));
     queue<P> Q;
     for (int i=; i<=n; ++i)
     {
         for (int j=; j<=m; ++j)
         {
             for (int l=; l<; ++l)
             {
                 dp[i][j][l] = INF;    inq[i][j][l] = false;
             }
         }
     }
     for (int i=; i<; ++i)
     {
         dp[x1][y1][i] = ;    inq[x1][y1][i] = true;
         Q.push ((P) {x1, y1, i});
     }

     while (!Q.empty ())
     {
         now = Q.front ();    Q.pop ();
         for (int i=; i<; ++i)
         {
             to.x = now.x + dx[i];
             to.y = now.y + dy[i];    to.z = i;
             if (check (to.x, to.y) && maze[to.x][to.y] == '.')
             {
                 int tmp = dp[now.x][now.y][now.z];
                 if (to.z == now.z)
                 {
                     if (tmp < dp[to.x][to.y][to.z])
                     {
                         dp[to.x][to.y][to.z] = tmp;
                         if (!inq[to.x][to.y][to.z])
                         {
                             inq[to.x][to.y][to.z] = true;    Q.push (to);
                         }
                     }
                 }
                 else
                 {
                     if (++tmp < dp[to.x][to.y][to.z])
                     {
                         dp[to.x][to.y][to.z] = tmp;
                         if (!inq[to.x][to.y][to.z])
                         {
                             inq[to.x][to.y][to.z] = true;    Q.push (to);
                         }
                     }
                 }
             }
         }
         inq[now.x][now.y][now.z] = false;
     }

     for (int i=; i<; ++i)
     {
         if (dp[x2][y2][i] <= k)    return true;
     }

     return false;
 }

 int main(void)        //HDOJ 1728 逃离迷宫
 {
 //    freopen ("HDOJ_1728.in", "r", stdin);

     int t;    scanf ("%d", &t);
     while (t--)
     {
         scanf ("%d%d", &n, &m);
         for (int i=; i<=n; ++i)    scanf ("%s", maze[i] + );
         scanf ("%d%d%d%d%d", &k, &y1, &x1, &y2, &x2);
         if (BFS ())    puts ("yes");
         else    puts ("no");
     }

     return ;
 }