Solution for Day 03

day_03/first.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+input = File.readlines './input'
+width = input.first.strip.size
+count = 0
+
+input.each_with_index do |row, i|
+  next if i == 0
+
+  count += 1 if row[(i * 3) % width] == '#'
+end
+puts count