public bool CheckVariant()
{
bool result = false;
if (mask != NumberType.all)
{
for (byte i = 1; i <= 9; i++)
{
var number = (NumberType)(1 << i - 1);
if ((mask & number) > 0)
{
continue;
}
int count = 0;
Cell _cell = null;
foreach (var cell in cells)
{
if ((cell.variant & number) == 0)
{
continue;
}
if (count++ != 0)
{
break;
}
_cell = cell;
}
if (count != 1)
{
continue;
}
_cell.SetValue(i);
result = true;
}
}
return(result);
}