POJ 1659 Frogs' Neighborhood

POJ 1659 Frogs' Neighborhood

题目大意：给出无向图每个顶点的度，试图构建一个符合条件的图。
见Havel-Hakimi定理。
以下是我的代码：

#include < algorithm >
#include < cstdio >
#include < cstring >
using   namespace  std;
const   int  kMaxn( 17 );

struct  Type
{
     int  num,degree;
};
bool   operator < ( const  Type  & a, const  Type  & b)
{
     return  (a.degree > b.degree  ||  (a.degree == b.degree  &&  a.num < b.num));
}

int  main()
{
     /*
    freopen("data.in","r",stdin);
    freopen("data.out","w",stdout);
    // */

     int  T;
    scanf( " %d " , & T);
     for ( int  case_num = 1 ;case_num <= T;case_num ++ )
    {
         int  n;
        Type r[kMaxn];
        scanf( " %d " , & n);
         for ( int  i = 1 ;i <= n;i ++ )
        {
            r[i].num = i;
            scanf( " %d " , & r[i].degree);
        }

         bool  success( true );
         int  g[kMaxn][kMaxn];
        memset(g, 0 ,kMaxn * kMaxn * sizeof ( int ));
         for ( int  i = 1 ;i <= n;i ++ )
        {
            sort(r + i,r + n + 1 );
             if (r[i].degree < 0 )
            {
                success = false ;
                 break ;
            }
             for ( int  j = i + 1 ;j <= n  &&  j <= i + r[i].degree;j ++ )
            {
                g[r[i].num][r[j].num] = g[r[j].num][r[i].num] = 1 ;
                r[j].degree -- ;
            }
        }

         if (case_num != 1 )
            printf( " \n " );
         if ( ! success)
            printf( " NO\n " );
         else
        {
            printf( " YES\n " );
             for ( int  i = 1 ;i <= n;i ++ )
            {
                 for ( int  j = 1 ;j <= n;j ++ )
                {
                     if (j != 1 )
                        printf( "   " );
                    printf( " %d " ,g[i][j]);
                }
                printf( " \n " );
            }
        }
    }

     return   0 ;
}