protected bool Step(HopOptions hopOptions, Func <Hop, bool> callback)
{
while (hopOptions.OptionAvailable)
{
Hop hop = hopOptions.CurrrentHop;
UndoStack.Push(hop);
if (callback(hop))
{
return(false);
}
List <Hop> allowedHops = board.GetAllowedHops();
bool cont = Step(new HopOptions(allowedHops), callback);
if (!cont)
{
return(false);
}
UndoStack.Pop();
board.UndoHopPeg(hop);
hopOptions.NextOptionIndex();
}
return(true);
}
/// <summary>
/// Move a peg to the empty "to" cell, removing the peg hopped over.
/// </summary>
public void HopPeg(Hop hop)
{
Assert.That(flatView[hop.FromCellIndex].HasPeg, "Expected from cell to be have a peg.");
Assert.That(flatView[hop.ToCellIndex].IsEmpty, "Expected to cell to be empty.");
Assert.That(flatView[hop.HoppedCellIndex].HasPeg, "Expected to cell have a peg.");
// Perform hop. From cell is emptied, cell being hopped is emptied, to cell is occupied.
flatView[hop.FromCellIndex].HasPeg = false;
flatView[hop.HoppedCellIndex].HasPeg = false;
flatView[hop.ToCellIndex].HasPeg = true;
// Save color state of from/hopped/to cells
hop.FromCellColor = flatView[hop.FromCellIndex].Color;
hop.HoppedCellColor = flatView[hop.HoppedCellIndex].Color;
hop.ToCellColor = flatView[hop.ToCellIndex].Color;
// Update color of To with color of From.
// We can ignore the others because the UI handles that.
flatView[hop.ToCellIndex].Color = hop.FromCellColor;
DoHop.Fire(this, new CellChangeEventArgs()
{
Hop = hop, State = true
});
}
protected bool SingleStepCallback(Hop hop)
{
board.HopPeg(hop);
Solved = board.RemainingPegs == 1;
hopSemaphore.WaitOne();
return(Solved);
}
/// <summary>
/// Return true if a solution has been found, which cancels the recursion.
/// </summary>
protected bool Callback(Hop hop)
{
++Iterations;
board.HopPeg(hop);
Solved = board.RemainingPegs == 1;
return(Solved);
}
public override Hop PushHop()
{
Hop hop = HopStack.Peek().CurrrentHop;
board.HopPeg(hop);
UndoStack.Push(hop);
return(hop);
}
public override void Run()
{
while (board.RemainingPegs > 1 && Step())
{
Hop hop = PushHop();
}
Solved = board.RemainingPegs == 1;
}
public override bool Step()
{
++Iterations;
bool ret = hopEnumerator.MoveNext();
if (ret)
{
Hop hop = hopEnumerator.Current;
board.HopPeg(hop);
ret = !(board.RemainingPegs == 1);
}
return(ret);
}
protected bool Unwind()
{
bool more = false;
while (!more && HopStack.Count > 0)
{
Hop undoHop = UndoStack.Pop();
board.UndoHopPeg(undoHop);
more = HopStack.Peek().NextOptionIndex();
if (!more)
{
HopStack.Pop();
}
}
return(more);
}
/// <summary>
/// The reverse process, restores pegs in the to cell, hopped cell, and removes the peg in the from cell.
/// </summary>
public void UndoHopPeg(Hop hop)
{
Assert.That(flatView[hop.FromCellIndex].IsEmpty, "Expected from cell to be empty.");
Assert.That(flatView[hop.ToCellIndex].HasPeg, "Expected to cell to have a peg.");
Assert.That(flatView[hop.HoppedCellIndex].IsEmpty, "Expected to cell to be empty.");
flatView[hop.FromCellIndex].HasPeg = true;
flatView[hop.HoppedCellIndex].HasPeg = true;
flatView[hop.ToCellIndex].HasPeg = false;
// Restore colors:
flatView[hop.FromCellIndex].Color = hop.FromCellColor;
flatView[hop.HoppedCellIndex].Color = hop.HoppedCellColor;
flatView[hop.ToCellIndex].Color = hop.ToCellColor;
UndoHop.Fire(this, new CellChangeEventArgs()
{
Hop = hop, State = false
});
}
protected IEnumerable <Hop> Step(HopOptions hopOptions)
{
while (hopOptions.OptionAvailable)
{
Hop hop = hopOptions.CurrrentHop;
UndoStack.Push(hop);
yield return(hop);
List <Hop> allowedHops = board.GetAllowedHops();
foreach (Hop nextHop in Step(new HopOptions(allowedHops)))
{
yield return(nextHop);
}
UndoStack.Pop();
board.UndoHopPeg(hop);
hopOptions.NextOptionIndex();
}
}
/// <summary>
/// We clone the Hop so that the color state is preserved for this *specific* hop.
/// Otherwise, the Hop instance might be re-used in a later iteration and the previous
/// Hop instance's color state will be overwritten by the new hop.
/// </summary>
/// <returns></returns>
public Hop Clone()
{
Hop hop = new Hop(FromCellIndex, ToCellIndex, HoppedCellIndex);
return(hop);
}
