PKU 2676 数独

PKU 2676 数独

http://acm.pku.edu.cn/JudgeOnline/problem?id=2676
#include < iostream >
#include < algorithm >
#include < string >
#include < vector >
#include < cmath >
#include < map >
using   namespace  std;
int  a[ 10 ][ 10 ];
bool  row[ 10 ][ 10 ],col[ 10 ][ 10 ],square[ 10 ][ 10 ];
struct  node
{
     int  x,y;
}q[ 81 ];
int  top;
int  getsquare( const   int   &  x, const   int   &  y)
{
     return  x / 3 * 3 + y / 3 ;
}
bool  check( const   int   &  x, const   int   &  y, const   int   &  k)
{
     return  (  ! row[x][k]  &&   ! col[y][k]  &&   ! square[getsquare(x,y)][k] );
}
bool  dfs()
{
    node tmp;
     if (top != 0 )
    {
        tmp = q[ -- top];
         for ( int  i = 1 ;i < 10 ;i ++ )
        {
             if (check(tmp.x,tmp.y,i))
            {
                row[tmp.x][i] = 1 ;
                col[tmp.y][i] = 1 ;
                square[getsquare(tmp.x,tmp.y)][i] = 1 ;
                 if (dfs())
                {
                    a[tmp.x][tmp.y] = i;
                     return   1 ;
                }
                 else
                {
                    row[tmp.x][i] = 0 ;
                    col[tmp.y][i] = 0 ;
                    square[getsquare(tmp.x,tmp.y)][i] = 0 ;
                }
            }
        }
        q[top ++ ] = tmp;
         return   0 ;
    }
     return   1 ;
}
int  main()
{
     int  t;
     char  s[ 10 ];
    scanf( " %d " , & t);
    getchar();
     while (t -- )
    {
        memset(col, false , sizeof (col));
        memset(row, false , sizeof (row));
        memset(square, false , sizeof (square));
        top = 0 ;
         for ( int  i = 0 ;i < 9 ;i ++ )
        {
            gets(s);
             for ( int  j = 0 ;j < 9 ;j ++ )
            {
                a[i][j] = s[j] - ' 0 ' ;
                 if (a[i][j] != 0 )
                {
                    row[i][a[i][j]] = 1 ;
                    col[j][a[i][j]] = 1 ;
                    square[getsquare(i,j)][a[i][j]] = 1 ;
                }
                 else
                {
                    q[top].x = i,q[top].y = j;
                    top ++ ;
                }
            }
        }
        dfs();
         for ( int  i = 0 ;i < 9 ;i ++ )
        {
             for ( int  j = 0 ;j < 9 ;j ++ )
                printf( " %d " ,a[i][j]);
            printf( " \n " );
        }
    }
}