Mercurial > repos > other > adventofcode2023
comparison day8.rb @ 11:a7fb64b48830
Implement Day 8 - node/map walking
Cheated on part 2 by finding out that the routes loop
and you need to do the lowest-common-multiple to get a VERY
large number
| author | IBBoard <dev@ibboard.co.uk> |
|---|---|
| date | Sat, 09 Dec 2023 16:37:20 +0000 |
| parents | |
| children |
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| 10:25dda3397797 | 11:a7fb64b48830 |
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| 1 #! /usr/bin/env ruby | |
| 2 | |
| 3 if ARGV.length != 1 | |
| 4 abort("Incorrect arguments - needs input file") | |
| 5 elsif not File.exist? (ARGV[0]) | |
| 6 abort("File #{ARGV[0]} did not exist") | |
| 7 end | |
| 8 | |
| 9 file = ARGV[0] | |
| 10 | |
| 11 lines = File.open(file, "r").each_line(chomp: true) | |
| 12 | |
| 13 steps = lines.first.each_char.to_a.cycle | |
| 14 | |
| 15 node_lines = lines.drop(1).to_a | |
| 16 | |
| 17 #first_node, _ = node_lines[0].split("=") | |
| 18 #first_node.strip! | |
| 19 | |
| 20 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 | |
| 21 | |
| 22 cur_node = "AAA" | |
| 23 step_count = 0 | |
| 24 | |
| 25 while cur_node != "ZZZ" | |
| 26 step_count += 1 | |
| 27 cur_node = nodes[cur_node][steps.next] | |
| 28 end | |
| 29 | |
| 30 puts step_count |