aoc2025/day_04/2.rb

#!/usr/bin/env ruby
# frozen_string_literal: true

require_relative "grid"

class Main
  def run
    data = []
    $stdin.each_line do |line|
      data << line.chomp
    end

    @sum = 0

    removed_sum = 1
    grid = Grid.new(data)
    until removed_sum == 0
      removed_sum = 0
      (0...grid.rows.size).each do |row_index|
        (0...grid.columns.size).each do |column_index|
          next unless grid.cell_at(row_index, column_index).value == "@"

          memo = grid.cell_at(row_index, column_index).neighbours.reject do |cell|
            grid.cell_at(cell.row, cell.column).value != "@"
          end
          if memo.size < 4
            data[row_index][column_index] = "x"
            removed_sum += 1
          end
        end
      end
      @sum += removed_sum
      grid = Grid.new(data)
    end

    puts @sum
  end
end

Main.new.run