/// <summary>
/// Attempts to cut 2 locations from the current board, mirrored about a randomly chosen axis.
/// </summary>
/// <param name="Stream">An existing <see cref="Random"/> number generator</param>
/// <returns>If the result has a unique solution, then the new <see cref="Board"/>. Otherwise, the original</returns>
public Board Pair(Random Stream)
{
var result = new Board(_parent);
var Filled = _parent.Find.FilledLocations().ToList();
if (Filled.Count > 0)
{
Location loc = new Location(Filled[Stream.Next(Filled.Count)]);
result[loc] = 0;
if (Stream.Next(2) == 1)
{
result[loc.FlipHorizontal()] = 0;
}
else
{
result[loc.FlipVertical()] = 0;
}
if (result.ExistsUniqueSolution())
{
return(result);
}
}
return(_parent);
}
/// <summary>
/// Attempts to cut 4 locations from the current board, mirrored about both horizontal and vertical axes.
/// </summary>
/// <param name="Stream">An existing <see cref="Random"/> number generator</param>
/// <returns>If the result has a unique solution, then the new <see cref="Board"/>. Otherwise, the original</returns>
public Board Quad(Random Stream)
{
var result = new Board(_parent);
var Filled = _parent.Find.FilledLocations().ToList();
if (Filled.Count > 0)
{
Location loc = new Location(Filled[Stream.Next(Filled.Count)]);
result[loc] = 0;
result[loc.FlipHorizontal()] = 0;
result[loc.FlipVertical()] = 0;
result[loc.FlipHorizontal().FlipVertical()] = 0;
if (result.ExistsUniqueSolution())
return result;
}
return _parent;
}
