BFS+模拟 ZOJ 3865 Superbot

题目传送门

  1 /*
  2     BFS+模拟：dp[i][j][p] 表示走到i，j，方向为p的步数为多少；
  3             BFS分4种情况入队，最后在终点4个方向寻找最小值:)
  4 */
  5 #include <cstdio>
  6 #include <iostream>
  7 #include <algorithm>
  8 #include <cstring>
  9 #include <string>
 10 #include <queue>
 11 using namespace std;
 12
 13 const int MAXN = 1e2 + 10;
 14 const int INF = 0x3f3f3f3f;
 15 int dir[4][4][2] = {
 16 {{0, -1}, {0, 1}, {-1, 0}, {1, 0}},
 17 {{1, 0}, {0, -1}, {0, 1}, {-1, 0}},
 18 {{-1, 0}, {1, 0}, {0, -1}, {0, 1}},
 19 {{0, 1}, {-1, 0}, {1, 0}, {0, -1}}
 20 };
 21 int dp[12][12][4];
 22 int dp2[12][12][4];
 23 int ans[12][12][4];
 24 char maze[12][12];
 25 int sx, sy, ex, ey;
 26 int n, m, P;
 27
 28 bool ok(int nx, int ny, int np)
 29 {
 30     if (nx < 0 || nx >= n || ny < 0 || ny >= m)   return false;
 31     if (maze[nx][ny] == ‘*‘ || dp[nx][ny][np] != -1)   return false;
 32
 33     return true;
 34 }
 35
 36 void BFS(void)
 37 {
 38     int x, y, nx, ny, p, np;
 39     queue<int> q;
 40     q.push (sx);    q.push (sy);    q.push (0);
 41
 42     while (!q.empty ())
 43     {
 44         x = q.front (); q.pop ();
 45         y = q.front (); q.pop ();
 46         p = q.front (); q.pop ();
 47
 48         if (x == ex && y == ey && ans[x][y][p] == -1)
 49             ans[x][y][p] = dp[x][y][p];
 50
 51         nx = x + dir[dp[x][y][p]/P%4][p][0];
 52         ny = y + dir[dp[x][y][p]/P%4][p][1];
 53         if (ok (nx, ny, p))     //move robot, not move dir
 54         {
 55             dp[nx][ny][p] = dp[x][y][p] + 1;
 56             q.push (nx);    q.push (ny);    q.push (p);
 57         }
 58
 59         np = p + 1;
 60         if (np > 3)    np = 0;
 61         if (ok (x, y, np))        //not move robot, move dir to right
 62         {
 63             dp[x][y][np] = dp[x][y][p] + 1;
 64             q.push (x);    q.push (y);    q.push (np);
 65         }
 66
 67         np = p - 1;
 68         if (np < 0) np = 3;
 69         if (ok (x, y, np))        //not move robot, move dir to left
 70         {
 71             dp[x][y][np] = dp[x][y][p] + 1;
 72             q.push (x);    q.push (y);    q.push (np);
 73         }
 74
 75         if (dp[x][y][p] <= 200)        //not move
 76         {
 77             dp[x][y][p]++;
 78             q.push (x); q.push (y); q.push (p);
 79         }
 80     }
 81
 82     return ;
 83 }
 84
 85 int main(void)        //ZOJ 3865 Superbot
 86 {
 87     //freopen ("F.in", "r", stdin);
 88
 89     int t;
 90     scanf ("%d", &t);
 91     while (t--)
 92     {
 93         memset (dp, -1, sizeof (dp));
 94         memset (ans, -1, sizeof (ans));
 95
 96         scanf ("%d%d%d", &n, &m, &P);
 97
 98         for (int i=0; i<n; ++i) scanf ("%s", &maze[i]);
 99         for (int i=0; i<n; ++i)
100         {
101             for (int j=0; j<m; ++j)
102             {
103                 if (maze[i][j] == ‘@‘)  sx = i, sy = j;
104                 else if (maze[i][j] == ‘$‘) ex = i, ey = j;
105             }
106         }
107
108         dp[sx][sy][0] = 0;
109         BFS ();
110
111         int mn = INF;
112         for (int i=0; i<4; ++i)
113         {
114             if (ans[ex][ey][i] == -1)    continue;
115             mn = min (mn, ans[ex][ey][i]);
116         }
117
118         if (mn == INF)  printf ("YouBadbad\n");
119         else    printf ("%d\n", mn);
120     }
121
122     return 0;
123 }