UVa 141 The Spot Game

UVa 141 The Spot Game

题目大意是：在一个n×n棋盘上不断执行加入棋子或移除棋子的操作，判断在哪一步出现了之前出现过的局面（通过旋转可以得到的认为是同一个局面）。
用一个set来存储已经出现过的局面，每次得到一个新局面，把这个新局面的各种旋转一起加入到set中。
以下是我的代码：

#include < set >
#include < cstdio >
#include < cstring >
using   namespace  std;
const   int  kMaxn( 57 );

int  n;

struct  Type
{
     bool  r[kMaxn][kMaxn];
};
bool   operator < ( const  Type  & a, const  Type  & b)
{
     for ( int  i = 1 ;i <= n;i ++ )
         for ( int  j = 1 ;j <= n;j ++ )
             if (a.r[i][j] < b.r[i][j])
                 return   true ;
             else   if (a.r[i][j] > b.r[i][j])
                 return   false ;
     return   false ;
}

void  rotate(Type  & x)
{
    Type t;
     for ( int  i = 1 ;i <= n;i ++ )
         for ( int  j = 1 ;j <= n;j ++ )
            t.r[j][n - i + 1 ] = x.r[i][j];
    x = t;
}

int  main()
{
    #ifndef ONLINE_JUDGE
    freopen( " data.in " , " r " ,stdin);
    freopen( " data.out " , " w " ,stdout);
     #endif

     while (scanf( " %d " , & n) == 1   &&  n)
    {
         int  ans( - 1 );
        Type g;
         set < Type >  used;
        memset(g.r, false ,kMaxn * kMaxn * sizeof ( bool ));

         for ( int  i = 1 ;i <= 2 * n;i ++ )
        {
             int  x,y;
             char  ch;
            scanf( " %d%d %c " , & x, & y, & ch);
             if (ans !=- 1 )
                 continue ;
             if (ch == ' + ' )
                g.r[x][y] = true ;
             else
                g.r[x][y] = false ;
             if (used.count(g))
            {
                ans = i;
                 continue ;
            }
            Type t(g);
             for ( int  j = 1 ;j <= 4 ;j ++ )
            {
                used.insert(t);
                rotate(t);
            }
        }

         if (ans ==- 1 )
            printf( " Draw\n " );
         else   if (ans & 1 )
            printf( " Player 2 wins on move %d\n " ,ans);
         else
            printf( " Player 1 wins on move %d\n " ,ans);
    }

     return   0 ;
}