static void Main(string[] args)
{
var m = MatrixSpiralFilling.FillMatrix(6);
MatrixSpiralFilling.PrintMatrix(m, -3);
var idx = UnorderedSubstring.FindIndex("hggtyug7ghh7jf5lkj8kljk6fgg", "7ghf7jh");
Console.WriteLine(idx);
//TestDataSize();
}
/// <summary>
/// Fills the matrix in using whole numbers strating from 1. Moves from the matrix center in spiral direction up-->left-->down-->right.
/// </summary>
/// <param name="N">Matrix size.</param>
/// <returns>Filled in matrix.</returns>
public static int[,] FillMatrix(int N)
{
if (N < 1)
{
throw new Exception($"Invalid matrix size {N}. Should be 1 or greater.");
}
if (N == 1)
{
return new int[1, 1] {
{ 1 }
}
}
;
var m = new int[N, N];
var active = true; //Used for stopping. We are going to stop when we hit any non-zero cell
var step = 1; //Number of steps in one direction. When step becomes zero we change the direction
var dir = Direction.Up; //Movement direction
var currentCount = 1; //A counter to keep current number to put into a cell
int centerX = N / 2, centerY = N / 2;
m[centerY, centerX] = 1; //Filling in the centeral cell. We do it manually to align the step, as it needs step = 2, but next movement needs step = 1
for (int x = centerX, y = centerY - 1, sideCount = 1 /*passed edges number*/; active; ++sideCount)
{
var startDir = dir;
for (int i = step; i > 0; --i)
{
//Console.WriteLine($"{x} : {y}, {step}, {dir} = {currentCount + 1}, s={step}");
if (m[y, x] != 0)
{
active = false; //we heat a filled in cell, so we stop as there are no any cells left
break;
}
m[y, x] = ++currentCount;
MatrixSpiralFilling.MakeStep(ref x, ref y, dir);
if (!MatrixSpiralFilling.InBounds(N, x, y, dir)) //if we are out of the matrix we have to change the direction
{
MatrixSpiralFilling.ChangeDirection(ref x, ref y, ref dir);
}
}
//Each time, when we haven't reached the border, we need to change direction too
if (startDir == dir)
{
MatrixSpiralFilling.ChangeDirection(ref x, ref y, ref dir);
}
//We need to increase the movement size on each even number of passed edges
if (sideCount % 2 == 0)
{
step++;
}
}
return(m);
}
