解数独算法－－C++实现

  #include 
using namespace std;
//可选数字
int candidate[] = {1,2,3,4,5,6,7,8,9};
//标记这个空格是否为原始数据
int g_a[9][9] = {0};
//打印函数
void print( int (*a)[9] )
{
for( int i = 0; i < 9; i++ )
{
  for( int j = 0; j < 9; j++ )
  {
   cout << a[i][j] << " ";
  }
  cout << endl;
}
cout << endl;
}
//判断可以放哪些数字
void ConfirmCandidate( int (*a)[9], int i, int j )
{
for( int i_candidate = 0; i_candidate < 9; i_candidate++ )
  candidate[i_candidate] = i_candidate+1;
for( int colm = 0; colm < 9; colm++ )
{
  if( a[i][colm] != 0 )
   candidate[a[i][colm]-1] = 0;
}
for( int line = 0; line < 9; line++ )
{
  if( a[line][j] != 0 )
   candidate[a[line][j]-1] = 0;
}
for( int line = i/3*3; line < i/3*3+3; line++ )
{
  for( int colm = j/3*3; colm < j/3*3+3; colm++ )
   if( a[line][colm] != 0 )
    candidate[a[line][colm]-1] = 0;
}
}
//标记每个空格位置
void TotalNumbers( int (*a)[9], int i, int j )
{
for( int line = 0; line < i; line++ )
{
  for( int colm = 0; colm < j; colm++ )
   if( a[line][colm] == 0 )
   {
    g_a[line][colm] = 1;
   }
}
}
//判断所填数字是否正确
bool Judgeva lue( int (*a)[9],int i, int j )
{
//同一行有无重复数字
for( int colm = 0; colm < 9; colm++ )
{
  if( a[i][colm] == a[i][j] && j != colm )
   return false;
}
//同一列有无重复数字
for( int line = 0; line < 9; line++ )
{
  if( a[line][j] == a[i][j] && i != line )
   return false;
}
//一个3*3的方格内有无重复数字
for( int line = i/3*3; line < i/3*3+3; line++ )
{
  for( int colm = j/3*3; colm < j/3*3+3; colm++ )
   if( a[line][colm] == a[i][j] && i != line && j != colm )
    return false;
}
return true;
}
//判断是否成功
bool success( int(*a)[9], int i, int j )
{
if( i < 0 || j < 0 ) return false;
int line = i;
int colm = j;
for( ; line < 9; line++, colm = 0 )
{
  for( ; colm < 9; colm++ )
  {
   //cout << "line = " << line <<"  colm = " << colm << endl;
   //if( colm == 8 && line == 8 ) return true;
   if( a[line][colm] != 0 && g_a[line][colm] == 0 ) continue;
   ConfirmCandidate(a, line, colm);
   for(int c = 0; c < 9; c++ )
   {
    if( candidate[c] >





 a[line][colm] )
    {
     a[line][colm] = candidate[c];
     /*
     *TEST
     *测试可选数字
     */
     /*
     for(int i = 0; i < 9; i++ )
      cout << candidate[i] << " ";
     cout << endl << endl;
     */
     //print(a);
     //判断放入的值是否正确
     bool bRet = Judgeva lue( a, line, colm );
     if(!bRet) 
     {
      //cout << "bRet  is  false" << endl;
     }
     else{
      //cout << "bRet  is  true" << endl;
      break;
     }
    }
    else if( c == 8 && candidate[c] <= a[line][colm] )
    {
     //cout << "line = " << line <<"  colm = " << colm << endl;
     int set_colm = 8;
     a[line][colm] = 0;
     if( colm == 0 )
     {
      while( g_a[line-1][set_colm] == 0)
      {
       if( set_colm == 0) 
       {
        line--;
        set_colm = 8;
       }
       else set_colm--;
      }
      return success( a, line - 1, set_colm);
     }
     else{
      while( g_a[line][colm-1] == 0)
      {
       if( set_colm == 0) 
       {
        line--;
        set_colm = 8;
       }
       else colm--;
      }
      return success( a ,line, colm-1 );
     }
    }
   }
  }
}
return true;

}

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  int main()
{
//initialization
int a[9][9] = {
  {8,0,0,0,0,0,0,0,0},
  {0,0,3,6,0,0,0,0,0},
  {0,7,0,0,9,0,2,0,0},
  {0,5,0,0,0,7,0,0,0},
  {0,0,0,0,4,5,7,0,0},
  {0,0,7,1,0,0,0,3,0},
  {0,0,1,0,0,0,0,6,8},
  {0,0,8,5,0,0,0,1,0},
  {0,9,0,0,0,0,4,0,0}
};
   //test
/*
int a[9][9] = {
  {8,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,6,8},
  {0,0,0,0,0,0,0,0,0},
  {0,0,0,0,0,0,0,0,0}
};
*/ 
TotalNumbers( a, 9, 9 );
success( a, 0, 0 );
print(a);
}