private void Show(GameChart initChart)
{
// I must show per columns and NOT per row as when I scan an array
Console.WriteLine("----------------------");
for (int i = 0; i < gameSize; i++)
{
for (int j = 0; j < gameSize; j++)
{
Console.Write(initChart.GetElement(i, j) + " ");
if (j == 2 || j == 5)
{
Console.Write("| ");
}
}
Console.WriteLine();
if (i == 2 || i == 5 || i == 8)
{
Console.WriteLine("----------------------");
}
}
}
// This Method will scan the matrix to detect the first
// empty cell which can be solved without guessing
private bool Play()
{
// Reset the new Game
bool readyForGuessing = false;
bool impossible = false;
bool continueSolve = true;
while (continueSolve) // A new Matrix scan is requested
{
// Scan the chart as long as there are '0' and I have ONLY one possibility to choose
while (initChart.StillCellsToFill() && continueSolve)
{
continueSolve = false;
for (int i = 0; i < gameSize; i++)
{
for (int j = 0; j < gameSize; j++)
{
// I must initialize the collection of all sorrounding numbers
// each time I examine a new cell (i,j) in the chart game
allNumbers.Clear();
// I must initialize the collection of the potential hits
// each time I examine a new cell
hitsCollection.Clear();
if (initChart.GetElement(i, j) == 0)
{
// I found an empty cell and I can collect the numbers
// of column, row and block in List allNumbers
allNumbers = initChart.getAllNumbers(i, j);
// Now I check if all the numbers collected in the List allNumbers
// are missing ONLY one value from 1 to 9.
hitsNr = 0; // Nr of possible alternatives for a specific cell (i,j) of value 0
for (int k = 1; k <= gameSize; k++)
{
if (!allNumbers.Contains(k)) // True if 'k' is NOT in the Collected Numbers
{
hitsCollection.Add(k); // Update the Collection of Hits/guesses for the ROW
hitsNr++; // if current value is not in the list, increase the counter and go on
candidateNr = k; // candidateNr is the potential value to fill the position in the chart
}
}
// Here: hitsCollection contains ALL the alternatives to fill the 0 and hitsNr = how many alternatives I have!
// I found the FIRST candidate in the current ROW (i) to fill position (i,j) in myChart
// UPDATING THE CHART HERE!!
if (hitsNr == 1)
{
readyForGuessing = false;
continueSolve = true; // Try a new scan of the chart after update
initChart.SetElement(i, j, candidateNr); // Update chart and exit
// Console.WriteLine($"Found element with value {candidateNr} to fit in position [{i},{j}]");
// Console.ReadKey();
// Console.Clear();
// Show(initChart);
}
else if (hitsNr > 0) // More than ONE candidate in the current ROW (i)
{
if (readyForGuessing == true) // It means that I am still in guessing mode
{
//Console.ReadKey();
//Console.Clear();
//Show(initChart);
//Console.WriteLine($"Found {hitsNr} values to fit in position [{i},{j}]");
for (int m = 0; m < hitsNr; m++)
{
// trying set the element in the chart and the Solve
// this must survive along MANY nested calls to Play()
// Saving the current matrix before changing the 0 with one "guess"
// in a List internal to initChart object
// Before starting solving the new chart
initChart.SaveChartInList(initChart);
continueSolve = true;
// ************************************
Game current = SaveCurrentGame();
// Add now the current game in a global list!
backupList.Push(current);
//*******************************************
// Here I update the chart we want to try to solve with "one guess"
// Console.ReadKey();
initChart.SetElement(i, j, hitsCollection[m]); // Update chart and exit
//Console.Write("[");
//foreach (int k in hitsCollection)
//{
// Console.Write(k + ",");
//}
//Console.WriteLine("]");
//Console.WriteLine($"Trying {hitsCollection[m]} in position ({i},{j})");
//Console.WriteLine("NR. Alternatives: " + hitsNr);
//Show(initChart);
if (Play()) // shelf call to Play. True if I got it solved with current choice of value in hitsCollections
{
// Console.WriteLine("PLAY IS TrUE !!!!! Game Solved");
continueSolve = false;
// Console.ReadKey();
return(true); // Return if following tries are solved
}
// Console.WriteLine("I have tried " + hitsCollection[m] + ". I will try with next value");
}
// Í checked ALL numbers in one position (x,y) and the game was not solved with any of them
// I need to return to previous state and try other numbers.
if (backupList.Count != 0)
{
RetrievePreviousGame(backupList.Pop());
return(false);
}
} // Still in guessing mode (readyGuessing == true ?)
}
else // hitsNr == 0 I have not possible solutions for the cell! Need to go back to previous level!
{
impossible = true;
if (backupList.Count != 0)
{
RetrievePreviousGame(backupList.Pop());
return(false);
}
}
}
// else if myChart element is NOT empty I continue my search in the matrix
}
}
// I get here when I complete an entire scan of the Matrix
} // If get here if ContinueSolve = false OR no more 0s in matrix
// This is always true if I DON´T HAVE any single solutions in the matrix and I get stuck!
readyForGuessing = initChart.StillCellsToFill() && !impossible; // readyForGuessing =...
if (readyForGuessing)
{
// Console.WriteLine("I FOUND and solved all SINGLE CHOICES. NOW I can check the MULTICHOICES");
continueSolve = true; // Set TRUE if I want to try guesses
// Console.ReadKey();
}
else
{
continueSolve = false;
}
} // sudoku solved with the specific sequence of multichoices!
return(true);
}
