Day 2 Ruby solutions

Author: creideiki

02-1.rb

@@ -0,0 +1,27 @@
+#!/usr/bin/env ruby
+
+class Report
+  attr_accessor :levels, :differences
+
+  def initialize(line)
+    @levels = line.split.map(&:to_i)
+    gen_differences
+  end
+
+  def gen_differences
+    @differences = []
+    (@levels.size - 1).times do |i|
+      @differences << @levels[i + 1] - @levels[i]
+    end
+  end
+
+  def safe?
+    return false unless @differences.all?(&:negative?) or @differences.all?(&:positive?)
+
+    @differences.all? { |d| d.abs >= 1 and d.abs <= 3 }
+  end
+end
+
+lines = File.read('02.input').lines.map(&:strip)
+
+puts lines.count { |line| Report.new(line).safe? }

02-2.rb

@@ -0,0 +1,30 @@
+#!/usr/bin/env ruby
+
+class Report
+  attr_accessor :levels, :differences
+
+  def initialize(line)
+    @levels = line.split.map(&:to_i)
+  end
+
+  def safe_levels?(levels)
+    differences = []
+    (levels.size - 1).times do |i|
+      differences << levels[i + 1] - levels[i]
+    end
+
+    return false unless differences.all?(&:negative?) or differences.all?(&:positive?)
+
+    differences.all? { |d| d.abs >= 1 and d.abs <= 3 }
+  end
+
+  def safe?
+    return true if safe_levels? @levels
+
+    levels.combination(levels.size - 1).any? { |l| safe_levels? l }
+  end
+end
+
+lines = File.read('02.input').lines.map(&:strip)
+
+puts lines.count { |line| Report.new(line).safe? }