/// <summary>
/// When the File -> Save Game Unsolved menu item is chosen
/// </summary>
private void FileSaveGameUnsolvedClick(object sender, EventArgs e)
{
Grid unsolvedGrid = grid.Copy();
unsolvedGrid.ForEachSquare((row, col, val) =>
{
if (unsolvedGrid.IsEditable(row, col))
{
unsolvedGrid.Clear(row, col);
}
});
GameManager.SaveGame(unsolvedGrid);
}
/// <summary>
/// Helper function: count the blank squares in the given grid.
/// </summary>
/// <returns>the number of blank squares</returns>
private int CountBlank(Grid grid)
{
int nBlanks = 0;
grid.ForEachSquare((row, col, val) =>
{
if (val == 0)
{
nBlanks += 1;
}
});
return(nBlanks);
}
/// <summary>
/// When the player transitions from "edit grid" mode to "play this game" mode
/// </summary>
internal static void PlayThisPuzzle(Grid oldGrid, Form form)
{
// Set all the squares as non-editable
Grid grid = oldGrid.Copy();
grid.ForEachSquare((row, col, val) =>
{
if (val != 0)
{
grid.SetEditable(false, row, col);
}
});
// Tries to solve the grid. If the grid has no unique solution, warn first.
Grid copyGrid = grid.Copy(); // yes another copy; the solver will mess with this one.
bool result = (new Solver().Solve(copyGrid));
if (result)
{
SaveGame(grid);
form.Hide();
GameForm gform = new GameForm(grid, true);
gform.ShowDialog();
form.Close();
}
else
{
if (MessageBox.Show(copyGrid.IsFull()? "This puzzle can be solved in more than one way. Play anyway?" : "This puzzle cannot be solved. Play anyway?", "Unsolvable Puzzle", MessageBoxButtons.YesNo) == DialogResult.Yes)
{
SaveGame(grid);
form.Hide();
GameForm gform = new GameForm(grid, true);
gform.ShowDialog();
form.Close();
}
}
}
/// <summary>
/// Helper function: count the blank squares in the given grid.
/// </summary>
/// <returns>the number of blank squares</returns>
private int CountBlank(Grid grid)
{
int nBlanks = 0;
grid.ForEachSquare((row, col, val) =>
{
if (val == 0)
{
nBlanks+=1;
}
});
return nBlanks;
}
/// <summary>
/// Generates a grid with the given difficulty level.
/// </summary>
public Grid Generate(DifficultyLevel difficulty)
{
// Generates stuff
// 1. Randomnly fill in the top and left part of the grid.
// 2. Try to solve it
// 3. Until we have enough blanks:
// remove some blanks
// if it isn't uniquely solvable, add those two blanks again.
Grid grid = GenerateBlankGrid();
Grid result;
// Top row
List <int> row = Enumerable.Range(1, 9).OrderBy((i) => rand.Next()).ToList();
for (int i = 0; i < 9; i++)
{
grid.Set(row[i], false, i, 0);
}
// Top column
row = Enumerable.Range(1, 9).OrderBy((i) => rand.Next()).ToList();
row.Remove(grid.Get(0, 0));
for (int i = 0; i < 8; i++)
{
grid.Set(row[i], false, 0, i + 1);
}
if (solver.FindErrors(grid).Count > 0)
{
// This is not enough to guarantee correctness.
// If we get an invalid grid, try try again!
result = Generate(difficulty);
}
else
{
solver.Solve(grid);
// How many blanks do we need?
int targetBlanks = 0;
switch (difficulty)
{
case DifficultyLevel.Easy:
targetBlanks = 30;
break;
case DifficultyLevel.Medium:
targetBlanks = 45;
break;
case DifficultyLevel.Hard:
targetBlanks = 50;
break;
}
// Remove squares until we have the right number of blanks.
int tries = 0;
while (tries < 100 && CountBlank(grid) < targetBlanks)
{
Grid saveCopy = grid.Copy();
// Solving is expensive. Blanking squares is easy!
// When the grid is mostly full, you can blank squares
// in relative safety without generating a non-unique
// puzzle. When the puzzle gets more sparse, you
// need to be more careful.
// That's what we're doing here. Quick optimization.
for (int i = 0; i < (targetBlanks - CountBlank(grid)) / 2 + 1; i++)
{
MaybeRandomBlank(grid);
}
if (!solver.Solve(grid.Copy()))
{
// it failed
grid = saveCopy;
}
tries++;
}
//Console.WriteLine("Generated puzzle in " + tries + " tries with "+CountBlank(grid)+" blanks");
// Finally, set every square to be not editable
grid.ForEachSquare((r, c, val) =>
{
if (val != 0)
{
grid.SetEditable(false, r, c);
}
});
result = grid;
}
return(result);
}