poj 2488

 1 #include<iostream>
 2 #include <vector>
 3 #include<string> 
 4 using namespace std;
 5 
 6 int n, p, q, total;
 7 int area[26][26];
 8 int dirX[8] = {-1, 1, -2, 2, -2, 2, -1, 1};
 9 int dirY[8] = {-2, -2, -1, -1, 1, 1, 2, 2};
10 vector<int> orderX;
11 vector<int> orderY; 
12 int dfs(int x, int y, int sum)
13 {
14     //Èç¹ûÊÇ×îºóÒ»¸öÇÒÒѾ­³É¹¦; 
15     if(sum == total)
16     {
17         orderX.push_back(x);
18         orderY.push_back(y);
19         return 1;
20     }
21     
22     area[x][y] = 1;
23     int res = 0;
24     for(int i = 0; i < 8; ++i)
25     {
26             int nx = x+dirX[i];
27             int ny = y+dirY[i];
28             if(nx >= 0 && nx < p && ny >= 0 && ny < q && area[nx][ny] == -1)
29             {
30                 int temp = sum+1;
31                 res = dfs(nx, ny, temp);
32                 if(res)
33                 {
34                     orderX.push_back(x);
35                     orderY.push_back(y);
36                     break;
37                 }
38             }
39     }
40     if(!res)
41         area[x][y] = -1;
42     return res;
43 }
44 
45 void solver(int no)
46 {
47     memset(area, -1, sizeof(int)*676);
48     cout << "Scenario #"<< no <<":" << endl;
49     orderX.clear();
50     orderY.clear();
51     if(dfs(0, 0, 1))
52     {
53         
54         for(int i = orderX.size()-1; i >= 0; --i)
55         {
56             char c = 65 + orderY[i];
57             cout << c << orderX[i]+1;
58         }
59     }
60     else
61     {
62         cout << "impossible";
63     }
64         cout << endl << endl;;
65 }
66 
67 int main()
68 {
69     cin >> n;
70     for(int i = 0; i < n; ++i)
71     {
72         cin >> p >> q;
73         total = p * q;
74         solver(i+1);
75     }    
76     return 0;
77 }