ruby 2019 day 3

ruby/2019/3/bin/problem

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+#!/usr/bin/env ruby
+
+require "crossed_wires"
+
+cw = CrossedWires.for STDIN.read.chomp
+puts "Part 1: #{cw.closest_intersection.map(&:abs).sum}"
+puts "Part 2: #{cw.intersection_distances.min}"

ruby/2019/3/lib/crossed_wires.rb

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+require "set"
+
+class CrossedWires
+  attr_reader :wires
+  def initialize(wires)
+    @wires = wires
+  end
+
+  def self.for(input)
+    new input.split("\n").map { |line| Wire.for line }
+  end
+
+  def intersections
+    wires.map(&:positions).map(&:keys).reduce(&:&)
+  end
+
+  def intersection_distances
+    intersections
+      .map { |intersection| wires.map { |wire| wire.positions[intersection] }.sum }
+  end
+
+  def closest_intersection
+    intersections
+      .map{ |intersection| intersection.split(",").map(&:to_i) }
+      .sort_by { |x, y| x.abs + y.abs }.min
+  end
+
+  class Wire
+    attr_reader :turns
+    def initialize(turns)
+      @turns = turns
+    end
+
+    def self.for(line)
+      new line.split(",").map { |turn| Turn.for turn }
+    end
+
+    def positions
+      @positions ||= begin
+                       x = 0
+                       y = 0
+                       current_distance = 0
+                       p = {}
+                       turns.each do |turn|
+                         turn.length.times do
+                           current_distance += 1
+                           case turn.dir
+                           when "U"
+                             y -= 1
+                           when "D"
+                             y += 1
+                           when "L"
+                             x -= 1
+                           when "R"
+                             x += 1
+                           end
+                           p["#{x},#{y}"] = current_distance unless p.key?("#{x},#{y}")
+                         end
+                       end
+                       p
+                     end
+    end
+  end
+
+  class Turn
+    attr_reader :dir, :length
+    def initialize(dir, length)
+      @dir = dir
+      @length = length
+    end
+
+    def self.for(string)
+      new string[0], string[1..].to_i
+    end
+  end
+end