Day 03

1 files changed, 37 insertions, 0 deletions

diff --git a/day03/part2 b/day03/part2
new file mode 100755
index 0000000..a772a1e
--- /dev/null
+++ b/day03/part2
@@ -0,0 +1,37 @@
+#!/usr/bin/env ruby
+
+input = $stdin.readlines.map(&:strip).map{|x|x.split(",")}
+
+def map_wire(wire_segments)
+  wire = []
+  x = 0
+  y = 0
+  wire_segments.each do |seg|
+    dir = seg[0]
+    len = seg[1..-1].to_i
+    len.times do
+      case dir
+      when "R"
+        x += 1
+      when "L"
+        x -= 1
+      when "U"
+        y += 1
+      when "D"
+        y -= 1
+      end
+      wire << [x, y]
+    end
+  end
+  wire
+end
+
+wire1 = map_wire(input[0])
+wire2 = map_wire(input[1])
+
+intersections = (wire1 & wire2) - [0,0]
+steps = intersections.map do |i|
+  wire1.index(i) + wire2.index(i) + 2
+end
+
+puts steps.min