private static bool CheckForNextMove(int[,] matrix, int currentRow, int currentCol)
{
var directions = new[]
{
"DownRight",
"Down",
"DownLeft",
"Left",
"UpLeft",
"Up",
"UpRight",
"Right"
};
for (int i = 0; i < directions.Length; i++)
{
var currentDirection = directions[i];
var deltas = DeltaUtils.GetDeltasByDirection(currentDirection);
var nextRow = currentRow + deltas.X;
var nextCol = currentCol + deltas.Y;
if (CheckIfNextMoveIsValid(matrix, nextRow, nextCol))
{
return true;
}
}
return false;
}
/// <summary>
/// A rotating walk in the matrix is walk that starts form the top left corner of the matrix and goes in down-right direction. When no continuation is available at the current direction , the direction is changed to the next possible clockwise.
/// </summary>
/// <param name="matrix">Matrix to fill.</param>
internal static void FillRotatingWalkMatrix(int[,] matrix)
{
var rows = matrix.GetLength(0);
var cols = matrix.GetLength(1);
int row = Constants.StartRow;
int col = Constants.StartCol;
int cellValue = Constants.CellsStartValue;
var direction = Constants.Directions[0];
var deltas = DeltaUtils.GetDeltasByDirection(direction);
bool hasFreeCells = true;
while (hasFreeCells)
{
matrix[row, col] = cellValue;
if (!CheckForNextMove(matrix, row, col))
{
int[] nextFreeCell = FindUnvisitedCell(matrix);
if ((nextFreeCell[0] > -1) && (nextFreeCell[1] > -1))
{
row = nextFreeCell[0];
col = nextFreeCell[1];
cellValue++;
direction = Constants.Directions[0];
deltas = DeltaUtils.GetDeltasByDirection(direction);
}
else
{
// All cells in matrix are filled.
hasFreeCells = false;
}
}
else
{
var nextRow = row + deltas.X;
var nextCol = col + deltas.Y;
if (!CheckIfNextMoveIsValid(matrix, nextRow, nextCol))
{
while (!CheckIfNextMoveIsValid(matrix, nextRow, nextCol))
{
direction = ChangeDirection(direction);
deltas = DeltaUtils.GetDeltasByDirection(direction);
nextRow = row + deltas.X;
nextCol = col + deltas.Y;
}
}
row += deltas.X;
col += deltas.Y;
cellValue++;
}
}
}