public void StackTracksCountForSegmentsCorrectly()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
stack.Push("3");
Assert.Equal(3, stack.Count);
using (stack.EnterSegment())
{
Assert.Equal(0, stack.Count);
stack.Push("4");
stack.Push("5");
stack.Push("6");
Assert.Equal(3, stack.Count);
stack.Pop();
stack.Pop();
stack.Pop();
Assert.Equal(0, stack.Count);
}
Assert.Equal(3, stack.Count);
}
public void CanCreateStackSegment()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
stack.Push("3");
using (stack.EnterSegment())
{
Assert.Equal(stack, Enumerable.Empty <string>());
stack.Push("4");
stack.Push("5");
stack.Push("6");
Assert.Equal(stack, new[] { "6", "5", "4" });
stack.Pop();
stack.Pop();
stack.Pop();
Assert.Equal(stack, Enumerable.Empty <string>());
}
Assert.Equal(stack, new[] { "3", "2", "1" });
}
public void CanEnumerateStackItems()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
stack.Push("3");
Assert.Equal(stack, new[] { "3", "2", "1" });
}
public void CannotPopEmptyStack()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
Assert.Equal("2", stack.Pop());
Assert.Equal("1", stack.Pop());
Assert.Throws <InvalidOperationException>(() => stack.Pop());
}
public void CanPushAndPopWithoutSegment()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
stack.Push("3");
Assert.Equal("3", stack.Pop());
Assert.Equal("2", stack.Pop());
Assert.Equal("1", stack.Pop());
}
public void CannotPopEmptySegment()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
stack.Push("3");
using (stack.EnterSegment())
{
Assert.Throws <InvalidOperationException>(() => stack.Pop());
}
}
public void CannotExitSegmentWithUnpoppedItems()
{
var stack = new SegmentedStack <string>();
stack.Push("1");
stack.Push("2");
stack.Push("3");
Assert.Equal(3, stack.Count);
var segment = stack.EnterSegment();
Assert.Equal(0, stack.Count);
stack.Push("4");
stack.Push("5");
stack.Push("6");
Assert.Equal(3, stack.Count);
stack.Pop();
Assert.Throws <InvalidOperationException>(() => segment.Dispose());
}
private void VisitAllPulls()
{
// Recursively visit all predecessors. This
// algorithm would be implemented most
// naturally as a depth-first recursive
// search, but doing so easily exhausts
// the call stack.
// Create a stack of moves that need to be processed.
IStack<Move> moves = new SegmentedStack<Move>();
// For all subsets of boxes on targets of the specified size.
foreach (Coordinate2D[] targets in CoordinateUtils.GetCoordinateSets(level.TargetCoordinates, level.Boxes))
{
// Check for cancel.
if (cancelInfo.Cancel)
{
return;
}
// Move the boxes into position.
level.MoveBoxes(targets);
// Add moves from all possible starting sokoban squares.
foreach (Coordinate2D coord in regionFinder.Coordinates)
{
pathFinder.Find(coord);
FindPulls(moves);
}
// Record position of pulls with no predecessors.
int index = moves.Count;
// While the stack is not empty.
while (!moves.IsEmpty)
{
// Check for cancel.
if (cancelInfo.Cancel)
{
return;
}
// Pop the next move off the stack.
Move move = moves.Pop();
int row = move.Row;
int column = move.Column;
Coordinate2D direction = move.Direction;
// If the move was previously searched, then undo it.
if (row < 0)
{
row = -row;
pathFinder.MoveBox(Operation.Push, row, column, row - direction.Row, column - direction.Column);
continue;
}
// Re-add the move as searched to undo it later.
moves.Push(new Move(-row, column, move.Direction));
// Check for move with no predecessor.
if (moves.Count <= index)
{
// Force a full search in preperation for
// an incremental search.
pathFinder.ForceFullCalculation();
}
// Execute the move and put the virtual sokoban on its normalized square.
pathFinder.MoveBoxAndIncrementalFind(Operation.Pull, row - direction.Row, column - direction.Column, row, column);
Coordinate2D sokobanCoord = pathFinder.GetFirstAccessibleCoordinate();
// If previously visited continue; otherwise add it to the set.
if (!visited.Add(sokobanCoord))
{
continue;
}
// Find all possible pulls from the current position and add them to the stack.
FindPulls(moves);
}
}
}
