久攻不克的搜索题

 

 

1.http://acm.hdu.edu.cn/showproblem.php?pid=1180

貌似就是只要分清楚各种情况就能AC，我自己觉得是该想的都想了，还是不能AC，只有先留着以后再做了。。

下面是这题的各种错误代码：

  1 #include <cstdio>
  2 #include <cstring>
  3 #include <queue>
  4 using namespace std;
  5 
  6 struct Pos
  7 {
  8     int x, y;
  9     int step;
 10 }S,E;
 11 char map[25][25];
 12 bool used[25][25];
 13 int dir[][2]={1,0, -1,0, 0,1, 0,-1};
 14 int n, m;
 15 
 16 bool Judge (Pos a)
 17 {
 18     if (a.x<0||a.x>n-1 || a.y<0||a.y>m-1 || used[a.x][a.y] || map[a.x][a.y]=='*')
 19         return false;
 20     return true;
 21 }
 22 
 23 int bfs ()
 24 {
 25     Pos Pre, Cur;
 26     queue <Pos> Q;
 27     while (!Q.empty ()) Q.pop();
 28     memset (used, 0, sizeof used);
 29 
 30     used[S.x][S.y] = true;
 31     Q.push (S);
 32     while (!Q.empty ())
 33     {
 34         Pre = Q.front ();
 35         Q.pop();
 36         for (int i=0; i<4; i++)
 37         {
 38             Cur = Pre;
 39             Cur.x += dir[i][0];
 40             Cur.y += dir[i][1];
 41             Cur.step += 1;
 42             if (Judge (Cur))
 43             {
 44                 if (map[Cur.x][Cur.y]=='|')
 45                 {
 46                     Pos tmp = Cur;
 47                     if ((i==2 || i==3) && Cur.step%2==0)
 48                     {
 49                         tmp.x = Cur.x + dir[i][0];
 50                         tmp.y = Cur.y + dir[i][1];
 51                         if (Judge (tmp))
 52                         {
 53                             used[tmp.x][tmp.y] = true;
 54                             Q.push (tmp);
 55                         }
 56                     }
 57                     else if ((i==0 || i==1) && Cur.step%2)
 58                     {
 59                         tmp.x = Cur.x + dir[i][0];
 60                         tmp.y = Cur.y + dir[i][1];
 61                         if (Judge (tmp))
 62                         {
 63                             used[tmp.x][tmp.y] = true;
 64                             Q.push (tmp);
 65                         }
 66                     }
 67                 }
 68                 else if (map[Cur.y][Cur.y]=='-')
 69                 {
 70                     Pos tmp = Cur;
 71                     if ((i==0 || i==1) && Cur.step%2==0)
 72                     {
 73                         tmp.x = Cur.x + dir[i][0];
 74                         tmp.y = Cur.y + dir[i][1];
 75                         if (Judge (tmp))
 76                         {
 77                             used[tmp.x][tmp.y] = true;
 78                             Q.push (tmp);
 79                         }
 80                     }
 81                     else if ((i==2 || i==3) && Cur.step%2)
 82                     {
 83                         tmp.x = Cur.x + dir[i][0];
 84                         tmp.y = Cur.y + dir[i][1];
 85                         if (Judge (tmp))
 86                         {
 87                             used[tmp.x][tmp.y] = true;
 88                             Q.push (tmp);
 89                         }
 90                     }
 91                 }
 92                 else if (map[Cur.x][Cur.y]=='T')
 93                     return Cur.step;
 94                 used[Cur.x][Cur.y] = true;
 95                 Q.push (Cur);
 96             }
 97         }
 98     }
 99     return -1;
100 }
101 int main()
102 {
103 //    freopen ("test.txt","r",stdin);
104     while (~scanf ("%d%d",&n, &m))
105     {
106         for (int i=0; i<n; i++)
107             for (int j=0; j<m;j++)
108             {
109                 scanf (" %c",map[i]+j);
110                 if (map[i][j] == 'S')
111                     S.x =i,S.y=j, S.step=0;
112                 else if (map[i][j]=='T')
113                     E.x=i, E.y=j;
114             }
115 
116         int ans = bfs();
117         printf ("%d\n",ans);
118     }
119     return 0;
120 }
View Code
  1 #include <cstdio>
  2 #include <cstring>
  3 #include <queue>
  4 using namespace std;
  5 
  6 struct Pos
  7 {
  8     int x, y;
  9     int step;
 10 }S,E;
 11 char map[25][25];
 12 bool used[25][25];
 13 int dir[][2]={1,0, -1,0, 0,1, 0,-1};
 14 int n, m;
 15 
 16 bool Judge (Pos a)
 17 {
 18     if (a.x<0||a.x>n-1 || a.y<0||a.y>m-1 || used[a.x][a.y] || map[a.x][a.y]=='*')
 19         return false;
 20     return true;
 21 }
 22 
 23 int bfs ()
 24 {
 25     Pos Pre, Cur;
 26     queue <Pos> Q;
 27     while (!Q.empty ()) Q.pop();
 28     memset (used, 0, sizeof used);
 29 
 30     used[S.x][S.y] = true;
 31     Q.push (S);
 32     while (!Q.empty ())
 33     {
 34         Pre = Q.front ();
 35         Q.pop();
 36         for (int i=0; i<4; i++)
 37         {
 38             Cur = Pre;
 39             Cur.x += dir[i][0];
 40             Cur.y += dir[i][1];
 41             Cur.step += 1;
 42             if (Judge (Cur))
 43             {
 44                 if (map[Cur.x][Cur.y]=='|')
 45                 {
 46                     Pos tmp = Cur;
 47                     if ((i==2 || i==3) && Cur.step%2==0)
 48                     {
 49                         tmp.x = Cur.x + dir[i][0];
 50                         tmp.y = Cur.y + dir[i][1];
 51                         if (Judge (tmp))
 52                         {
 53                             used[tmp.x][tmp.y] = true;
 54                             Q.push (tmp);
 55                         }
 56                     }
 57                     else if ((i==0 || i==1) && Cur.step%2)
 58                     {
 59                         tmp.x = Cur.x + dir[i][0];
 60                         tmp.y = Cur.y + dir[i][1];
 61                         if (Judge (tmp))
 62                         {
 63                             used[tmp.x][tmp.y] = true;
 64                             Q.push (tmp);
 65                         }
 66                     }
 67                     else
 68                     {
 69                         Cur.step++;
 70                         Q.push(Cur);
 71                         continue;
 72                     }
 73                 }
 74                 else if (map[Cur.y][Cur.y]=='-')
 75                 {
 76                     Pos tmp = Cur;
 77                     if ((i==0 || i==1) && Cur.step%2==0)
 78                     {
 79                         tmp.x = Cur.x + dir[i][0];
 80                         tmp.y = Cur.y + dir[i][1];
 81                         if (Judge (tmp))
 82                         {
 83                             used[tmp.x][tmp.y] = true;
 84                             Q.push (tmp);
 85                         }
 86                     }
 87                     else if ((i==2 || i==3) && Cur.step%2)
 88                     {
 89                         tmp.x = Cur.x + dir[i][0];
 90                         tmp.y = Cur.y + dir[i][1];
 91                         if (Judge (tmp))
 92                         {
 93                             used[tmp.x][tmp.y] = true;
 94                             Q.push (tmp);
 95                         }
 96                     }
 97                     else
 98                     {
 99                         Cur.step++;
100                         Q.push (Cur);
101                         continue;
102                     }
103                 }
104                 else if (map[Cur.x][Cur.y]=='T')
105                     return Cur.step;
106                 used[Cur.x][Cur.y] = true;
107                 Q.push (Cur);
108             }
109         }
110     }
111     return -1;
112 }
113 int main()
114 {
115 //    freopen ("test.txt","r",stdin);
116     while (~scanf ("%d%d",&n, &m))
117     {
118         for (int i=0; i<n; i++)
119             for (int j=0; j<m;j++)
120             {
121                 scanf (" %c",map[i]+j);
122                 if (map[i][j] == 'S')
123                     S.x =i,S.y=j, S.step=0;
124                 else if (map[i][j]=='T')
125                     E.x=i, E.y=j;
126             }
127 
128         int ans = bfs();
129         printf ("%d\n",ans);
130     }
131     return 0;
132 }
View Code
  1 #include <cstdio>
  2 #include <cstring>
  3 #include <queue>
  4 #define Min(a, b) (a < b ? a : b)
  5 using namespace std;
  6 
  7 struct Pos
  8 {
  9     int x, y;
 10     int step;
 11 }S,E;
 12 char map[25][25];
 13 bool used[25][25];
 14 int dir[][2]={1,0, -1,0, 0,1, 0,-1};
 15 int n, m;
 16 
 17 bool Judge (Pos a)
 18 {
 19     if (a.x<0||a.x>n-1 || a.y<0||a.y>m-1 || used[a.x][a.y] || map[a.x][a.y]=='*')
 20         return false;
 21     return true;
 22 }
 23 
 24 int bfs ()
 25 {
 26     int ans = 0x3f3f3f3f;
 27     Pos Pre, Cur;
 28     queue <Pos> Q;
 29     while (!Q.empty ()) Q.pop();
 30     memset (used, 0, sizeof used);
 31 
 32     used[S.x][S.y] = true;
 33     Q.push (S);
 34     while (!Q.empty ())
 35     {
 36         Pre = Q.front ();
 37         Q.pop();
 38         for(int i=0; i<4; i++)
 39         {
 40             Cur = Pre;
 41             Cur.x += dir[i][0];
 42             Cur.y += dir[i][1];
 43             Cur.step += 1;
 44             if (map[Cur.x][Cur.y]=='T')
 45                 ans = Min(ans, Cur.step);
 46             if (Judge (Cur))
 47             {
 48                 if (map[Cur.x][Cur.y]=='|')
 49                 {
 50                     if ((Pre.step%2==0 && (i==2 || i==3)) || (Pre.step%2==1 && (i==1 || i==0)))
 51                     {
 52                         Cur.x += dir[i][0];
 53                         Cur.y += dir[i][1];
 54                         if (Judge (Cur))
 55                         {
 56                             if(map[Cur.x][Cur.y]=='T')
 57                                 ans = Min (ans, Cur.step);
 58                             used[Cur.x][Cur.y] = true;
 59                             Q.push (Cur);
 60                         }
 61                     }
 62                     else
 63                     {
 64                         Cur.x += dir[i][0];
 65                         Cur.y += dir[i][1];
 66                         Cur.step += 1;
 67                         if (Judge (Cur))
 68                         {
 69                             if (map[Cur.x][Cur.y]=='T')
 70                                 ans = Min (ans, Cur.step);
 71                             used[Cur.x][Cur.y] = true;
 72                             Q.push (Cur);
 73                         }
 74                     }
 75                     continue;
 76                 }
 77                 else if (map[Cur.x][Cur.y]=='-')
 78                 {
 79                     if ((Pre.step%2==0 && (i==0 || i==1)) || (Pre.step%2==1 && (i==2 || i==3)))
 80                     {
 81                         Cur.x += dir[i][0];
 82                         Cur.y += dir[i][1];
 83                         if (Judge (Cur))
 84                         {
 85                             if (map[Cur.x][Cur.y]=='T')
 86                                 ans = Min (ans, Cur.step);
 87                             used[Cur.x][Cur.y] = true;
 88                             Q.push (Cur);
 89                         }
 90                     }
 91                     else
 92                     {
 93                         Cur.x += dir[i][0];
 94                         Cur.y += dir[i][1];
 95                         Cur.step += 1;
 96                         if (Judge (Cur))
 97                         {
 98                             if (map[Cur.x][Cur.y]=='T')
 99                                 ans = Min (ans, Cur.step);
100                             used[Cur.x][Cur.y] = true;
101                             Q.push (Cur);
102                         }
103                     }
104                     continue;
105                 }
106                 else if (map[Cur.x][Cur.y] == 'T')
107                     ans = Min (ans, Cur.step);
108 
109                 used[Cur.x][Cur.y] = true;
110             
111                 Q.push (Cur);
112             }
113         }
114     }
115     return ans;
116 }
117 int main()
118 {
119 //    freopen ("test.txt","r",stdin);
120     while (~scanf ("%d%d",&n, &m))
121     {
122         for (int i=0; i<n; i++)
123             for (int j=0; j<m;j++)
124             {
125                 scanf (" %c",map[i]+j);
126                 if (map[i][j] == 'S')
127                     S.x =i,S.y=j, S.step=0;
128             }
129 
130         int ans = bfs();
131     
132         printf ("%d\n",ans);
133     }
134     return 0;
135 }
View Code
  1 #include <cstdio>
  2 #include <cstring>
  3 #include <queue>
  4 using namespace std;
  5 #define N 250
  6 
  7 struct Pos
  8 {
  9     int x, y;
 10     int step;
 11 }S;
 12 char map[N][N];
 13 bool used[N][N];
 14 int n, m, dir[][2]={1,0, -1,0, 0,1, 0,-1};
 15 
 16 bool Judge (Pos a)
 17 {
 18     if (a.x<0||a.x>n-1 || a.y<0||a.y>m-1 || used[a.x][a.y] || map[a.x][a.y]=='*')
 19         return false;
 20     return true;
 21 }
 22 
 23 int bfs ()
 24 {
 25     Pos Pre, Cur;
 26     queue <Pos> Q;
 27     memset (used, 0, sizeof used);
 28 
 29     used[S.x][S.y] = true;
 30     Q.push (S);
 31     while (!Q.empty())
 32     {
 33         Pre = Q.front();
 34         Q.pop();
 35         if (map[Pre.x][Pre.y] == 'T')
 36             return Pre.step;
 37         for (int i=0; i<4; i++)
 38         {
 39             Cur = Pre;
 40             Cur.x += dir[i][0];
 41             Cur.y += dir[i][1];
 42             Cur.step += 1;
 43             if (Judge (Cur))
 44             {
 45                 Pos tmp = Cur;
 46                 if (map[Cur.x][Cur.y]=='|')
 47                 {
 48                     if ((Pre.step%2==1 && (i==0 || i==1)) || (Pre.step%2==0 && (i==2 || i==3)))
 49                     {
 50                         tmp.x += dir[i][0];
 51                         tmp.y    += dir[i][1];
 52                         Q.push (tmp);
 53                     }
 54                     else
 55                     {
 56                         tmp.x += dir[i][0];
 57                         tmp.y += dir[i][1];
 58                         tmp.step += 1;
 59                         Q.push (tmp);
 60                     }
 61                     used[tmp.x][tmp.y] = true;
 62                 }
 63                 else if (map[Cur.x][Cur.y]=='-')
 64                 {
 65                     if ((Pre.step%2==1 && (i==2 || i==3)) || (Pre.step%2==0 && (i==0 || i==1)))
 66                     {
 67                         tmp.x += dir[i][0];
 68                         tmp.y += dir[i][1];
 69                         Q.push (tmp);
 70                     }
 71                     else
 72                     {
 73                         tmp.x += dir[i][0];
 74                         tmp.y += dir[i][1];
 75                         tmp.step += 1;
 76                         Q.push (tmp);
 77                     }
 78                     used[tmp.x][tmp.y] = true;
 79                 }
 80                 used[Cur.x][Cur.y] = true;
 81                 Q.push (Cur);
 82             }
 83         }
 84     }
 85     return -1;
 86 }
 87 
 88 int main()
 89 {
 90     while (~scanf ("%d%d",&n, &m))
 91     {
 92         for (int i=0; i<n; i++)
 93             for (int j=0; j<m; j++)
 94             {
 95                 scanf (" %c",map[i]+j);
 96                 if (map[i][j]=='S')
 97                     S.x=i, S.y=j, S.step=0;
 98             }
 99         int ans = bfs ();
100         printf ("%d\n",ans);
101     }
102     return 0;
103 }
View Code
 1 #include <cstdio>
 2 #include <cstring>
 3 #include <queue>
 4 using namespace std;
 5 
 6 struct Pos 
 7 {
 8     int x, y;
 9     int step;
10 }S;
11 int n, m;
12 char map[21][21];
13 bool used[21][21];
14 int dir[][2]={{1,0},{-1,0},{0,1},{0,-1}};
15 
16 void CreatMap ()
17 {
18     for (int i=0; i<m; i++)
19             for (int j=0; j<n; j++)
20             {
21                 scanf (" %c",&map[i][j]);
22                 if (map[i][j]=='S')
23                 {
24                     S.x = i;    S.y = j;
25                 }
26             }
27 }
28 
29 bool Judge (Pos a)
30 {
31     if (a.x<0||a.x>n-1 || a.y<0||a.y>m-1 || used[a.x][a.y] || map[a.x][a.y]=='*')
32         return false;
33     return true;
34 }
35 
36 int BFS ()
37 {
38     queue <Pos> Q;
39     Pos Pre, Cur;
40     memset (used, 0, sizeof (used));
41 
42     S.step = 0;
43     used[S.x][S.y] = true;
44     Q.push (S);
45     while (!Q.empty ())
46     {
47         Pre = Q.front ();
48         Q.pop ();
49         if (map[Pre.x][Pre.y]=='T')
50             return Pre.step;
51 
52         for (int i=0; i<4; i++)
53         {
54             Cur = Pre;
55             Cur.x += dir[i][0];
56             Cur.y += dir[i][1];
57             Cur.step += 1;
58 
59             if (Judge (Cur))
60             {
61                 if (map[Cur.x][Cur.y]=='-' || map[Cur.x][Cur.y]=='|')
62                 {
63                     Pos tmp = Cur;
64                     tmp.x += dir[i][0];
65                     tmp.y += dir[i][1];
66                     if (Judge (tmp))
67                     {
68                         if ((map[Cur.x][Cur.y]=='|' && Pre.step%2==1 && i>1) ||
69                             (map[Cur.x][Cur.y]=='|' && Pre.step%2==0 && i<2) ||
70                             (map[Cur.x][Cur.y]=='-' && Pre.step%2==1 && i<2) ||
71                             (map[Cur.x][Cur.y]=='-' && Pre.step%2==0 && i>1))
72                             tmp.step++;
73 
74                         used[tmp.x][tmp.y] = true;
75                         Q.push (tmp);
76                     }
77                 }
78                 else
79                 {
80                     used[Cur.x][Cur.y] = true;
81                     Q.push (Cur);
82                 }
83             }
84         }
85     }
86     return -1;
87 }
88 
89 int main ()
90 {
91     while (~scanf ("%d%d",&m,&n))
92     {
93         CreatMap ();
94 
95         printf ("%d\n",BFS ());
96     }
97     return 0;
98 }
View Code

 

 

2.http://acm.hdu.edu.cn/showproblem.php?pid=1045

题意：在一个正方形中，‘X'表示墙，’.'表示空地。可以再空地上放上大炮。因为在同一行或同一列的大炮且没有强隔开的直线上，大炮可以相互攻击，问你在大炮不能相互攻击的情况下可以摆放的最多的大炮数是多少？？？

posted @ 2014-11-01 17:24  无道圣君  阅读(166)  评论(0)  编辑  收藏  举报