add day_05

day_05/1.rb

@@ -0,0 +1,28 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+class Main
+  def run
+    ranges = []
+    ingredient_ids = Hash.new(0)
+    $stdin.each_line do |line|
+      arr = line.chomp.split("-").map(&:to_i)
+      if arr.size == 2
+        ranges << (arr[0]..arr[1])
+      elsif arr.size == 1
+        ingredient_ids[arr[0]] += 1
+      end
+    end
+
+    @sum = 0
+    ingredient_ids.each do |id, count|
+      if ranges.any? { |r| r.include?(id) }
+        @sum += count
+      end
+    end
+
+    puts @sum
+  end
+end
+
+Main.new.run

day_05/2.rb

@@ -0,0 +1,47 @@
+#!/usr/bin/env ruby
+# frozen_string_literal: true
+
+class Main
+  def run
+    ranges = []
+    $stdin.each_line do |line|
+      arr = line.chomp.split("-").map(&:to_i)
+      if arr.size == 2
+        ranges << (arr[0]..arr[1])
+      end
+    end
+
+    # Sort ranges by starting point
+    # This prevents having to check all previous ranges for every new range
+    ranges.sort_by!(&:begin)
+
+    valid_id_ranges = []
+    ranges.each do |r|
+      valid_id_ranges.each do |vr|
+        if (
+            # r starts inside vr
+            r.begin >= vr.begin && r.begin <= vr.end) ||
+            # r ends inside vr
+            (r.end >= vr.begin && r.end <= vr.end) ||
+            # vr starts inside r
+            (vr.begin >= r.begin && vr.begin <= r.end) ||
+            # vr ends inside r
+            (vr.end >= r.begin && vr.end <= r.end)
+          # Merge ranges
+          r = ([r.begin, vr.begin].min..[r.end, vr.end].max)
+          valid_id_ranges.delete(vr)
+        end
+      end
+      valid_id_ranges << r
+    end
+
+    @total = 0
+    valid_id_ranges.each do |r|
+      @total += (r.end - r.begin + 1)
+    end
+
+    puts @total
+  end
+end
+
+Main.new.run