POJ 2243

 1 #include <iostream>
 2 #include <queue>
 3 using namespace std;
 4 
 5 int dir[8][2] = {-2,-1,-2,1,2,-1,2,1,1,-2,-1,-2,1,2,-1,2};
 6 
 7 struct node
 8 {
 9     int x;
10     int y;
11     int step;
12     node()
13     {
14         step = 0;
15     }
16 };
17 
18 queue<node> coll;
19 
20 bool mark[8][8];
21 
22 node beg;
23 node end;
24 
25 bool bfs(node p);
26 
27 int main()
28 {
29     //freopen("acm.acm","r",stdin);
30     char s_1[2];
31     char s_2[2];
32 
33     while(cin>>s_1>>s_2)
34     {
35         memset(mark,false,sizeof(mark));
36         beg.x = s_1[0] - ‘a‘;
37         beg.y = s_1[1] - ‘0‘ - 1;
38         
39         end.x = s_2[0] - ‘a‘;
40         end.y = s_2[1] - ‘0‘ - 1;
41         coll.push(beg);
42         mark[beg.x][beg.y] = true;
43         cout<<"To get from "<<s_1<<" to "<<s_2<<" takes ";
44         
45         while(!coll.empty() && !bfs(coll.front()))
46         {
47             coll.pop();
48         }
49         while(!coll.empty())
50         {
51             coll.pop();
52         }
53         cout<<" knight moves."<<endl;
54     }
55 }
56 
57 bool bfs(node p)
58 {
59     int i;
60     int j;
61     if(p.x == end.x && p.y == end.y)
62     {
63         cout<<p.step;
64         return true;
65     }
66     int tem_i;
67     int tem_j;
68     node tem;
69     
70     for(i = 0; i < 8; ++ i)
71     {
72         tem_i = p.x + dir[i][0];
73         tem_j = p.y + dir[i][1];
74         if(tem_i >= 0 && tem_i < 8 && tem_j >= 0 && tem_j < 8 && !mark[tem_i][tem_j])
75         {
76             tem.x = tem_i;
77             tem.y = tem_j;
78             tem.step = p.step + 1;
79             mark[tem_i][tem_j] = true;
80             coll.push(tem);
81         }
82     }
83     return false;
84 }