uva 1378博弈

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 using namespace std;
 5 
 6 const int N = 25;
 7 int a[N];
 8 int sg[N];
 9 
10 void init()
11 {
12     sg[0] = 0;
13     bool visit[N << 1];
14     for ( int i = 1; i < N; i++ )
15     {
16         memset( visit, 0, sizeof(visit) );
17         for ( int j = 0; j < i; j++ )
18         {
19             for ( int k = 0; k <= j; k++ )
20             {
21                 visit[sg[j] ^ sg[k]] = 1;
22             }
23         }
24         int l;
25         for ( l = 0; visit[l]; l++ ) ;
26         sg[i] = l;
27     }
28 }
29 
30 int main ()
31 {
32     init();
33     int n, _case = 1;
34     while ( cin >> n, n )
35     {
36         int ans = 0;
37         for ( int i = 0; i < n; i++ )
38         {
39             cin >> a[i];
40             if ( a[i] & 1 )
41             {
42                 ans = ans ^ sg[n - 1 - i];
43             }
44         }
45         if ( !ans )
46         {
47             cout << "Game " << _case++ << ": -1 -1 -1" << endl;
48         }
49         else
50         {
51             bool flag = false;
52             for ( int i = 0; i < n && !flag; i++ )
53             {
54                 if ( !a[i] ) continue;
55                 for ( int j = i + 1; j < n && !flag; j++ )
56                 {
57                     for ( int k = j; k < n; k++ )
58                     {
59                         int tmp = ans ^ sg[n - 1 - i] ^ sg[n - 1 - j] ^ sg[n - 1 - k];
60                         if ( !tmp )
61                         {
62                             cout << "Game " << _case++ << ": " << i << ‘ ‘ << j << ‘ ‘ << k << endl;
63                             flag = true;
64                             break;
65                         }
66                     }
67                 }
68             }
69         }
70     }
71     return 0;
72 }