public StepNode(NineSquareElement startElement = null, int index = -1, bool rotated = false, bool bt = false)
{
StartAtElement = startElement;
ElementIndex = index;
RotateCW = rotated;
BT = bt;
}
public static NineSquareElement[] GetElementsNear(ref NineSquareElement elementRelatedTo,
ref NineSquareElement[] nineSquareElements)
{
if ((nineSquareElements?.Count() ?? 0) < 9)
return null;
var index = IndexOf(elementRelatedTo, nineSquareElements);
if (index == -1) return null;
int row = index/3;
int col = index%3;
NineSquareElement[] elements = new NineSquareElement[4];
//Console.WriteLine("l t r b : {0} {1} {2} {3}", (col - 1 < 0 ? 2 : col - 1) + (row*3),
// col + ((row - 1 < 0 ? 2 : row - 1)*3), ((col + 1)%3) + (row*3), col + (((row + 1)%3)*3));
// left
elements[0] = nineSquareElements[(col - 1 < 0 ? 2 : col - 1) + (row*3)];
// top
elements[1] = nineSquareElements[col + ((row - 1 < 0 ? 2 : row - 1)*3)];
// right
elements[2] = nineSquareElements[((col + 1)%3) + (row*3)];
// bottom
elements[3] = nineSquareElements[col + (((row + 1)%3)*3)];
return elements;
}
public static bool CheckSolvable(NineSquareElement[] elements)
{
int result = 0;
// check non-null and element count == 9
if ((elements?.Count() ?? 0) != 9)
return false;
// add up all edges
// should return 0 if valid.
elements.ToList()
.ForEach(
element =>
result +=
element.EdgeLeftWeight + element.EdgeTopWeight + element.EdgeRightWeight +
element.EdgeBottomWeight);
return result == 0;
}
private void button1_Click(object sender, EventArgs e)
{
NineSquareElement[] elements = new NineSquareElement[9];
for (int i = 0; i < 9; i++)
{
int left = 0, right = 0, top = 0, bottom = 0;
var textBox = FindControl("textBox" + (i + 1) + "l") as TextBox;
int.TryParse(textBox.Text.Trim(), out left);
textBox = FindControl("textBox" + (i + 1) + "t") as TextBox;
int.TryParse(textBox.Text.Trim(), out top);
textBox = FindControl("textBox" + (i + 1) + "r") as TextBox;
int.TryParse(textBox.Text.Trim(), out right);
textBox = FindControl("textBox" + (i + 1) + "b") as TextBox;
int.TryParse(textBox.Text.Trim(), out bottom);
NineSquareElement element = new NineSquareElement(left, top, right, bottom);
elements[i] = element;
}
NineSquarePuzzle puzzle = new NineSquarePuzzle(elements);
if (!NineSquarePuzzle.CheckSolvable(elements))
MessageBox.Show("Invalid Puzzle..", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
if (puzzle.Solve())
{
for (int i = 0; i < 9; i++)
{
int left = 0, right = 0, top = 0, bottom = 0;
var textBox = FindControl("textBox" + (i + 1) + "l") as TextBox;
textBox.Text = puzzle.SolvedNineSquareElements[i].EdgeLeftWeight.ToString();
textBox = FindControl("textBox" + (i + 1) + "t") as TextBox;
textBox.Text = puzzle.SolvedNineSquareElements[i].EdgeTopWeight.ToString();
textBox = FindControl("textBox" + (i + 1) + "r") as TextBox;
textBox.Text = puzzle.SolvedNineSquareElements[i].EdgeRightWeight.ToString();
textBox = FindControl("textBox" + (i + 1) + "b") as TextBox;
textBox.Text = puzzle.SolvedNineSquareElements[i].EdgeBottomWeight.ToString();
}
}
}
public static int IndexOf(NineSquareElement element, NineSquareElement[] elements)
{
var index = -1;
for (var i = 0; i < 9; i++)
{
if (elements[i] == element)
index = i;
}
return index;
}
private void Revert(ref NineSquareElement[] oldElements, ref NineSquareElement[] newElements)
{
if (oldElements == null) return;
if (newElements == null) newElements = new NineSquareElement[9];
oldElements.CopyTo(newElements, 0);
for (int i = 0; i < 9; i++)
{
if (i + 1 < 9)
newElements[i].ForwardElement = newElements[i + 1];
else
newElements[i].ForwardElement = null;
}
}
public bool LoadPuzzle(NineSquareElement[] puzzleElements)
{
bool validPuzzle = CheckSolvable(puzzleElements);
if (validPuzzle)
{
NineSquareElements = puzzleElements;
for (int i = 0; i < 9; i++)
{
if (i + 1 < 9)
NineSquareElements[i].ForwardElement = NineSquareElements[i + 1];
else
NineSquareElements[i].ForwardElement = null;
}
}
return validPuzzle;
}
public NineSquarePuzzle(NineSquareElement[] puzzleElements = null)
{
LoadPuzzle(puzzleElements);
}
public bool BT(NineSquareElement start, ref NineSquareElement[] nineSquareElements)
{
int rotateCount = 0;
NineSquareElement[] oldElements = null;
// used here to clone current elements into oldElements
Revert(ref nineSquareElements, ref oldElements);
if (VerifySolved(nineSquareElements))
return true;
++nestedCount;
while (start != null)
{
var elements = GetElementsNear(ref start, ref nineSquareElements);
if (rotateCount <= 3)
{
if (VerifySolved(nineSquareElements))
{
--nestedCount;
return true;
}
else if (BT(start.ForwardElement, ref nineSquareElements))
{
--nestedCount;
// verify this particular node.
return true;
}
else if (rotateCount <= 3)
{
// Check & Rotate
StepsToSolve.Enqueue(new StepNode((NineSquareElement) start.Clone(),
IndexOf(start, nineSquareElements), true));
NineSquarePuzzle puzzle = new NineSquarePuzzle(nineSquareElements);
VisualPuzzleSolve.Enqueue(puzzle);
start.RotateCW();
rotateCount++;
}
else if (rotateCount > 3 && start != nineSquareElements[0])
{
// backtrack
//Console.WriteLine("BT...");
StepsToSolve.Enqueue(new StepNode((NineSquareElement) start.Clone(),
IndexOf(start, nineSquareElements), false, true));
Revert(ref oldElements, ref nineSquareElements);
NineSquarePuzzle puzzle = new NineSquarePuzzle(nineSquareElements);
VisualPuzzleSolve.Enqueue(puzzle);
}
else
{
--nestedCount;
return false;
}
}
else
{
--nestedCount;
return false;
}
}
--nestedCount;
return false;
}
public static bool VerifySolved(NineSquareElement[] elements)
{
if (elements?.Count() != 9) return false;
int i = 0;
bool result = true;
foreach (var element in elements)
{
var directionalElements = GetElementsNear(ref elements[i++], ref elements);
if (element.EdgeLeftWeight + directionalElements[0].EdgeRightWeight != 0 ||
element.EdgeTopWeight + directionalElements[1].EdgeBottomWeight != 0 ||
element.EdgeRightWeight + directionalElements[2].EdgeLeftWeight != 0 ||
element.EdgeBottomWeight + directionalElements[3].EdgeTopWeight != 0)
{
result = false;
break;
}
}
return result;
}
public static void PrintPuzzle(NineSquareElement[] elements)
{
string line1 = "", line2 = "", line3 = "";
string s = "";
int i = 0;
for (i = 0; i <= 9; i++)
{
if (i%3 == 0 && i != 0)
{
s = line1 + "\n" + line2 + "\n" + line3 + "\n" + new string('-', 16*3 + 5);
line1 = "";
line2 = "";
line3 = "";
Console.WriteLine(s);
if (i == 9)
break;
}
line1 += "\t" + elements[i].EdgeTopWeight + "\t | ";
line2 += elements[i].EdgeLeftWeight + "\t\t" + elements[i].EdgeRightWeight +
" | ";
line3 += "\t" + elements[i].EdgeBottomWeight + "\t | ";
}
}
