public SudokuGrid ConstructGrid()
{
SudokuGrid grid = new SudokuGrid
{
Cells = new Cell[9][]
};
for (int i = 0; i < 9; i++)
{
grid.Cells[i] = new Cell[9];
for (int j = 0; j < 9; j++)
{
grid.Cells[i][j] = new Cell
{
BlockLoc = (i / 3) * 3 + (j / 3) + 1,//Block number = row/3*3+column/3
Candidates = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
},
Num = '0',
ReadOnly = true,
XLocation = i,
YLocation = j
};
}
}
AddNeighbours(grid);
return(grid);
}
/// <summary>
///
/// </summary>
/// <returns>the puzzle in form of SudokuGrid</returns>
public SudokuGrid Setter()
{
PuzzleSolverAdvDS solve = new PuzzleSolverAdvDS();
SudokuGrid grid = ConstructGrid();
//Using Backtracking Solver to fill in a blank grid to get a starting solution - possibly the part of the generator that causes performance issues
bool testing = false;//testing condition
if (!testing)
{
try
{
if (!solve.CompileBacktracker(grid, 2))
{
MessageBox.Show("Generator did not find a puzzle to generate");
}
}
catch (Exception ex)
{
MessageBox.Show("Something has gone terribly wrong...\r\nError: " + ex);
return(grid);
}
}
else
{
#region Manual Testing Puzzle
StringToGrid(grid, "600438079900705080800000032200004060000000000040600003180000005070806001560941008");
#endregion
}
RemoveNumbers(grid, solve);
return(grid);
}
/// <summary>
/// Function that recieves a puzzle and the string version of the puzzle and tests the difficulty of the puzzle by solving it using the Human-Strategy solver
/// </summary>
/// <param name="puzzleGrid"></param>
/// <param name="puzzleString"></param>
/// <returns>returns the difficulty rating of the puzzle</returns>
public long GetDifficulty(SudokuGrid puzzleGrid, string puzzleString, PuzzleSolverAdvDS solver)
{
long rating = 0;
int counter = 0;
for (int x = 0; x < 9; x++)
{
for (int y = 0; y < 9; y++)
{
if (puzzleString[counter] == '0')
{
puzzleGrid.Cells[x][y].Candidates = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};
}
else
{
puzzleGrid.Cells[x][y].Candidates = new List <char> {
};
}
puzzleGrid.Cells[x][y].Num = puzzleString[counter];
counter++;
}
}
solver.Solver(puzzleGrid, 1);
rating = solver.g_Rating;
puzzleGrid.Difficulty = solver.g_Difficulty;
return(rating);
}
/// <summary>
/// checks for if the puzzle is valid in the sense that is has more than 7 unique numbers at any point in the puzzle, more than 16 givens, and one solution
/// </summary>
/// <param name="grid"></param>
/// <returns></returns>
public bool CheckValidity(SudokuGrid grid)
{
bool minOfEight = false;
int givens = 0;
List <char> numList = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};
for (int x = 0; x < 9; x++)
{
for (int y = 0; y < 9; y++)
{
if (grid.Cells[x][y].Num != '0')
{
numList.Remove(grid.Cells[x][y].Num);
if (numList.Count <= 1)
{
minOfEight = true;
}
givens++;
}
}
}
if (!minOfEight || givens < 17)
{
return(false);
}
char[][] sudokuArray = new char[9][] { new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9] };
for (int r = 0; r < 9; r++)
{
for (int c = 0; c < 9; c++)
{
sudokuArray[r][c] = grid.Cells[r][c].Num;
}
}
PuzzleSolverAdvDS solve = new PuzzleSolverAdvDS();
if (solve.CompileBacktracker(grid, 4))
{
string firstSol = GridToString(grid);
grid = RestartPuzzle(grid, sudokuArray);
if (solve.CompileBacktracker(grid, 1))
{
string secSol = GridToString(grid);
if (firstSol == secSol)//valid puzzle
{
grid = RestartPuzzle(grid, sudokuArray);
return(true);
}
else
{
grid = RestartPuzzle(grid, sudokuArray);
return(false);
}
}
}
return(true);
}
/// <summary>
/// Reassigns the values in the puzzle to what they were prior to being solved
/// </summary>
/// <param name="grid"></param>
/// <param name="sudokuArray">contains the original puzzle prior to solve</param>
/// <returns></returns>
public SudokuGrid RestartPuzzle(SudokuGrid grid, char[][] sudokuArray)
{
for (int x = 0; x < 9; x++)//O(n^2)
{
for (int y = 0; y < 9; y++)
{
grid.Cells[x][y].Num = sudokuArray[x][y];
}
}
return(grid);
}
/// <summary>
/// Takes a SudokuGrid object and converts into a char[][] type
/// </summary>
/// <param name="grid"></param>
/// <param name="puzzle"></param>
/// <returns></returns>
private char[][] SudokuGridToArray(SudokuGrid grid, char[][] puzzle)
{
for (int x = 0; x < 9; x++)
{
for (int y = 0; y < 9; y++)
{
puzzle[x][y] = grid.Cells[x][y].Num;
}
}
return(puzzle);
}
/// <summary>
/// This converts a SudokuGrid into a string of numbers from 0-9, where 0 is an empty cell
/// </summary>
/// <param name="grid"></param>
/// <returns></returns>
public string GridToString(SudokuGrid grid)
{
string sudokuExport = "";
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
sudokuExport += grid.Cells[i][j].Num;
}
}
return(sudokuExport);
}
public bool ValidateInput(UniformGrid SudokuPuzzle, SudokuGrid g_grid, TextBox g_selectedCell)
{
if (g_selectedCell.Text == "")
{
return(true);
}
double index_ = SudokuPuzzle.Children.IndexOf(g_selectedCell);
int row = (int)index_ / 9;
int col = (int)index_ % 9;
g_grid.Cells[row][col].Num = g_selectedCell.Text[0];
if (g_grid.Cells[row][col].Num == '0')
{
return(true);
}
bool valid = true;
for (int n = 0; n < 8; n++)
{
if (g_grid.Cells[row][col].Num == g_grid.Cells[row][col].NeighbourCells[0][n].Num)
{
int index = g_grid.Cells[row][col].NeighbourCells[0][n].XLocation * 9 + g_grid.Cells[row][col].NeighbourCells[0][n].YLocation;
if (((TextBox)SudokuPuzzle.Children[index]).Background != Brushes.Red)
{
g_grid.Cells[row][col].Num = '0';
valid = false; break;
}
}
if (g_grid.Cells[row][col].Num == g_grid.Cells[row][col].NeighbourCells[1][n].Num)
{
int index = g_grid.Cells[row][col].NeighbourCells[1][n].XLocation * 9 + g_grid.Cells[row][col].NeighbourCells[1][n].YLocation;
if (((TextBox)SudokuPuzzle.Children[index]).Background != Brushes.Red)
{
g_grid.Cells[row][col].Num = '0';
valid = false; break;
}
}
if (g_grid.Cells[row][col].Num == g_grid.Cells[row][col].NeighbourCells[2][n].Num)
{
int index = g_grid.Cells[row][col].NeighbourCells[2][n].XLocation * 9 + g_grid.Cells[row][col].NeighbourCells[2][n].YLocation;
if (((TextBox)SudokuPuzzle.Children[index]).Background != Brushes.Red)
{
g_grid.Cells[row][col].Num = '0';
valid = false; break;
}
}
}
return(valid);
}
/// <summary>
/// For each cell, add all neighbouring cells to the list of cells property
/// </summary>
/// <param name="grid"></param>
public void AddNeighbours(SudokuGrid grid)
{
for (int i = 0; i < 9; i++)
{
for (int j = 0; j < 9; j++)
{
int nbCounter = 0;//nbCounter is neighbourcounter
grid.Cells[i][j].NeighbourCells = new Cell[3][]
{
new Cell[8],
new Cell[8],
new Cell[8]
};
for (int k = 0, p = 0; k < 9; k++)
{
if (j != k)
{
grid.Cells[i][j].NeighbourCells[0][p++] = grid.Cells[i][k];//add neighbour in i
nbCounter++;
}
}
nbCounter = 0;
for (int l = 0, p = 0; l < 9; l++)
{
if (l != i)
{
grid.Cells[i][j].NeighbourCells[1][p++] = grid.Cells[l][j];//add neighbour in column
nbCounter++;
}
}
nbCounter = 0;
int[] blockIndexes = BlockIndexGetter(grid.Cells[i][j].BlockLoc);
for (int x = blockIndexes[0], p = 0; x < blockIndexes[0] + 3; x++)
{
for (int y = blockIndexes[1]; y < blockIndexes[1] + 3; y++)
{
if (grid.Cells[x][y] != grid.Cells[i][j])
{
grid.Cells[i][j].NeighbourCells[2][p++] = grid.Cells[x][y];//add neighbour in block
nbCounter++;
}
}
}
}
}
}
/// <summary>
/// Used to check if the puzzle is solved
/// </summary>
/// <param name="grid"></param>
/// <returns></returns>
public bool CheckIfSolved(SudokuGrid grid)
{
for (int row = 0; row < 9; row++)
{
List <char> numberList = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};
for (int col = 0; col < 9; col++)
{
if (grid.Cells[row][col].Num == '0')
{
if (grid.Cells[row][col].Candidates.Count == 0)
{
MessageBox.Show("A strategy has malfunctioned and caused a contradiction or the puzzle is invalid");//Catches if a strategy makes a mistake by causing a cell to have no candidates
}
return(false);
}
else if (numberList.Contains(grid.Cells[row][col].Num))
{
numberList.Remove(grid.Cells[row][col].Num);
}
for (int index = 0; index < 3; index++)
{
for (int i = 0; i < 8; i++)
{
if (grid.Cells[row][col].NeighbourCells[index][i].Num == grid.Cells[row][col].Num)
{
return(false);
}
}
}
}
if (numberList.Count > 0)
{
return(false);
}
}
return(true);
}
public void StringToGrid(SudokuGrid puzzleGrid, string puzzleString)
{
int counter = 0;
for (int x = 0; x < 9; x++)
{
for (int y = 0; y < 9; y++)
{
if (puzzleString[counter] == '0')
{
puzzleGrid.Cells[x][y].Candidates = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};
}
else
{
puzzleGrid.Cells[x][y].Candidates = new List <char> {
};
}
puzzleGrid.Cells[x][y].Num = puzzleString[counter];
counter++;
}
}
}
public void RemoveNumbers(SudokuGrid grid, PuzzleSolverAdvDS solve)
{
///This section consists of constantly removing parallel numbers, e.g. [0,0] and [8,8] or [2,5] and [5,2], and checking if the puzzle is still valid (i.e. still has only one solution)
int removed = 0;
List <string> cellsChecked = new List <string>(81);
List <int> rowList = new List <int> {
0, 1, 2, 3, 4, 5, 6, 7, 8
};
List <int> colList = new List <int> {
0, 1, 2, 3, 4, 5, 6, 7, 8
};
rowList = Shuffler_intList(rowList);
colList = Shuffler_intList(colList);
foreach (int row in rowList)
{
if (removed >= g_MaxRemoves)
{
break;
}
foreach (int col in colList)
{
if (removed >= g_MaxRemoves)
{
break;
}
if (!cellsChecked.Contains(row.ToString() + col.ToString()))
{
int altRow = NumberSwitch(row);
int altCol = NumberSwitch(col);
if (grid.Cells[altRow][altCol].Num != '0' && grid.Cells[row][col].Num != '0')
{
bool valid = false;
List <char> numList = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};
for (int x = 0; x < 9 && !valid; x++)//checks for if the puzzle is valid in the sense that is has more than 7 unique numbers at any point in the puzzle
{
for (int y = 0; y < 9 && !valid; y++)
{
if (grid.Cells[x][y].Num != '0')
{
if ((x == altRow && y == altCol) == false && (x == row && y == col) == false)
{
numList.Remove(grid.Cells[x][y].Num);
}
if (numList.Count <= 1)
{
valid = true;
}
}
}
}
if (valid)
{
char[][] sudokuArray = new char[9][] { new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9] };
for (int r = 0; r < 9; r++)
{
for (int c = 0; c < 9; c++)
{
sudokuArray[r][c] = grid.Cells[r][c].Num;
}
}
grid.Cells[row][col].Num = '0';
grid.Cells[altRow][altCol].Num = '0';
if (solve.CompileBacktracker(grid, 4))
{
string firstSol = GridToString(grid);
grid = RestartPuzzle(grid, sudokuArray);
grid.Cells[row][col].Num = '0';
grid.Cells[altRow][altCol].Num = '0';
if (solve.CompileBacktracker(grid, 1))//tries Backtracking algorithm using reversed candidate lists so that if a solution that is different to the previous solution exists, it will be found, invalidating the puzzle
{
string secSol = GridToString(grid);
if (firstSol == secSol)//valid puzzle
{
grid = RestartPuzzle(grid, sudokuArray);
grid.Cells[row][col].Num = '0';
grid.Cells[altRow][altCol].Num = '0';
if (grid.Cells[row][col] == grid.Cells[altRow][altCol])
{
removed++;
}
else
{
removed += 2;
}
}
else//Multiple solutions
{
grid = RestartPuzzle(grid, sudokuArray);
}
}
}
else//Invalid puzzle, should never occur
{
grid = RestartPuzzle(grid, sudokuArray);
}
}
if (grid.Cells[row][col] == grid.Cells[altRow][altCol])
{
cellsChecked.Add(row.ToString() + col.ToString());
}
else
{
cellsChecked.Add(row.ToString() + col.ToString());
cellsChecked.Add(altRow.ToString() + altCol.ToString());
}
}
}
}
}
if (removed < g_MaxRemoves)
{
cellsChecked = new List <string>();
foreach (int row in rowList)
{
if (removed >= g_MaxRemoves)
{
break;
}
foreach (int col in colList)
{
if (removed >= g_MaxRemoves)
{
break;
}
if (!cellsChecked.Contains(row.ToString() + col.ToString()))
{
if (grid.Cells[row][col].Num != '0')
{
bool valid = false;
List <char> numList = new List <char> {
'1', '2', '3', '4', '5', '6', '7', '8', '9'
};
for (int x = 0; x < 9 && !valid; x++)//checks for if the puzzle is valid in the sense that is has more than 7 unique numbers at any point in the puzzle
{
for (int y = 0; y < 9 && !valid; y++)
{
if (grid.Cells[x][y].Num != '0')
{
if ((x == row && y == col) == false)
{
numList.Remove(grid.Cells[x][y].Num);
}
if (numList.Count <= 1)
{
valid = true;
}
}
}
}
if (valid)
{
char[][] sudokuArray = new char[9][] { new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9], new char[9] };
for (int r = 0; r < 9; r++)
{
for (int c = 0; c < 9; c++)
{
sudokuArray[r][c] = grid.Cells[r][c].Num;
}
}
grid.Cells[row][col].Num = '0';
if (solve.CompileBacktracker(grid, 4))
{
string firstSol = GridToString(grid);
grid = RestartPuzzle(grid, sudokuArray);
grid.Cells[row][col].Num = '0';
if (solve.CompileBacktracker(grid, 1))
{
string secSol = GridToString(grid);
if (firstSol == secSol)//valid puzzle
{
grid = RestartPuzzle(grid, sudokuArray);
grid.Cells[row][col].Num = '0';
removed++;
}
else
{
grid = RestartPuzzle(grid, sudokuArray);
}
}
}
else
{
grid = RestartPuzzle(grid, sudokuArray);
}
}
}
cellsChecked.Add(row.ToString() + col.ToString());
}
}
}
}
}