Example spiral-matrix implementation

exercises/practice/spiral-matrix/.meta/example.rb

@@ -0,0 +1,48 @@
+class SpiralMatrix
+  private
+  attr_reader :counter, :dx, :dy, :x, :y
+
+  def initialize_matrix
+    Array.new(size) { Array.new(size, 0) }
+  end
+
+  def generate_matrix
+    while matrix_includes_zeroes?
+      @matrix[y][x] = counter
+
+      @dy, @dx = @dx, -@dy if next_step_invalid?
+
+      @x += dx
+      @y += dy
+
+      @counter += 1
+    end
+  end
+
+  def next_step_invalid?
+    @y + @dy == @size ||
+      (@y + @dy).negative? ||
+      @x + @dx == @size ||
+      (@x + @dx).negative? ||
+      !(@matrix[@y + @dy][@x + @dx]).zero?
+  end
+
+  def matrix_includes_zeroes?
+    @matrix.any? { |row| row.any?(0) }
+  end
+
+  public
+  attr_reader :size, :matrix
+
+  def initialize(size)
+    @size = size
+    @matrix = initialize_matrix
+    @dx = 1
+    @dy = 0
+    @y = 0
+    @x = 0
+    @counter = 1
+
+    generate_matrix
+  end
+end