use deletaged methods

use single instance of Grid

day_04/1.rb

@@ -13,8 +13,8 @@ class Main
     @sum = 0
 
     grid = Grid.new(data)
-    (0...grid.rows.size).each do |row_index|
+    (0...grid.size).each do |row_index|
-      (0...grid.columns.size).each do |column_index|
+      (0...grid[row_index].size).each do |column_index|
         cell = grid.cell_at(row_index, column_index)
         next unless cell.value == "@"
 

day_04/2.rb

@@ -15,15 +15,15 @@ class Main
     grid = Grid.new(data)
     loop do
       grid_updated = false
-      (0...grid.rows.size).each do |row_index|
+      (0...grid.size).each do |row_index|
-        (0...grid.columns.size).each do |column_index|
+        (0...grid[row_index].size).each do |column_index|
           cell = grid.cell_at(row_index, column_index)
           next unless cell.value == "@"
 
           if cell.neighbours.count do |neighbour|
             neighbour.value == "@"
           end < 4
-            data[row_index][column_index] = "x"
+            grid[row_index][column_index].value = "x"
             @sum += 1
             grid_updated = true
           end
@@ -31,7 +31,6 @@ class Main
       end
 
       break unless grid_updated
-      grid = Grid.new(data)
     end
 
     puts @sum

day_04/grid.rb

@@ -1,10 +1,14 @@
+require "forwardable"
+
 require_relative "cell"
 
 class Grid
-  attr_reader :rows, :columns
+  attr_reader :columns
+  extend Forwardable
+  def_delegators :@data, :size, :[]
 
   def initialize(input)
-    @rows = []
+    @data = []
     (0...input.size).each do |row_index|
       row = []
       (0...input[row_index].size).each do |column_index|
@@ -12,27 +16,26 @@ class Grid
         cell.value = input[row_index][column_index]
         row << cell
       end
-      @rows << row
+      @data << row
     end
-    @columns = @rows.transpose
 
     # Link neighbours
-    (0...@rows.size).each do |row_index|
+    (0...@data.size).each do |row_index|
-      (0...@columns.size).each do |column_index|
+      (0...@data[row_index].size).each do |column_index|
-        cell = @rows[row_index][column_index]
+        cell = @data[row_index][column_index]
-        cell.n = @rows[row_index - 1][column_index] if row_index - 1 >= 0
+        cell.n = @data[row_index - 1][column_index] if row_index - 1 >= 0
-        cell.ne = @rows[row_index - 1][column_index + 1] if row_index - 1 >= 0 && column_index + 1 < @columns.size
+        cell.ne = @data[row_index - 1][column_index + 1] if row_index - 1 >= 0 && column_index + 1 < @data[row_index - 1].size
-        cell.e = @rows[row_index][column_index + 1] if column_index + 1 < @columns.size
+        cell.e = @data[row_index][column_index + 1] if column_index + 1 < @data[row_index].size
-        cell.se = @rows[row_index + 1][column_index + 1] if row_index + 1 < @rows.size && column_index + 1 < @columns.size
+        cell.se = @data[row_index + 1][column_index + 1] if row_index + 1 < @data.size && column_index + 1 < @data[row_index + 1].size
-        cell.s = @rows[row_index + 1][column_index] if row_index + 1 < @rows.size
+        cell.s = @data[row_index + 1][column_index] if row_index + 1 < @data.size
-        cell.sw = @rows[row_index + 1][column_index - 1] if row_index + 1 < @rows.size && column_index - 1 >= 0
+        cell.sw = @data[row_index + 1][column_index - 1] if row_index + 1 < @data.size && column_index - 1 >= 0
-        cell.w = @rows[row_index][column_index - 1] if column_index - 1 >= 0
+        cell.w = @data[row_index][column_index - 1] if column_index - 1 >= 0
-        cell.nw = @rows[row_index - 1][column_index - 1] if row_index - 1 >= 0 && column_index - 1 >= 0
+        cell.nw = @data[row_index - 1][column_index - 1] if row_index - 1 >= 0 && column_index - 1 >= 0
       end
     end
   end
 
   def cell_at(row, column)
-    @rows[row][column]
+    @data[row][column]
   end
 end