--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/day8b.rb	Sat Dec 09 16:37:20 2023 +0000
@@ -0,0 +1,33 @@
+#! /usr/bin/env ruby
+
+if ARGV.length != 1
+        abort("Incorrect arguments - needs input file")
+elsif not File.exist? (ARGV[0])
+	abort("File #{ARGV[0]} did not exist")
+end
+
+file = ARGV[0]
+
+lines = File.open(file, "r").each_line(chomp: true)
+
+steps = lines.first.each_char.to_a
+
+node_lines = lines.drop(1).to_a
+
+#first_node, _ = node_lines[0].split("=")
+#first_node.strip!
+
+nodes = node_lines.map {|line| node, rest = line.split("="); left, right = rest.split(","); [node.strip, {"L" => left.strip[1..-1], "R" => right.strip[0..-2]}]}.to_h
+
+cur_nodes = nodes.keys.filter {|v| v[-1] == "A"}
+
+step_counts = cur_nodes.map do |cur_node| 
+	step_count = 0
+	step_cycle = steps.cycle
+	while cur_node[-1] != "Z"
+		step_count += 1
+		cur_node = nodes[cur_node][step_cycle.next]
+	end
+	step_count
+end
+puts step_counts.reduce(1, :lcm)
\ No newline at end of file