Mercurial > repos > other > adventofcode2023
view day9.rb @ 26:eb6c3a7d2f72
Constrained and more optimised route finding
* Track routes so we can see if we have gone straight for
too long
* Track multiple routes so we can use a non-optimal route to
X if it makes another route to Y through X possible (e.g.
optimal route takes three consecutive steps to X, but then
has to turn, whereas a longer straight earlier and two
consecutive steps to X gives a much better next hop to Y)
* We have a start point, so only include the nodes from the
search front in "unvisited" to avoid looking at lots of
irrelevant nodes
author | IBBoard <dev@ibboard.co.uk> |
---|---|
date | Sun, 17 Dec 2023 20:13:03 +0000 |
parents | 891878e52a31 |
children |
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#! /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] histories = File.open(file, "r").each_line(chomp: true).map {|line| line.split(" ").map(&:to_i)} def diff_array(arr) arr.each_cons(2) end predictions = histories.map do |history| vals = history layers = [history] while not vals.all? {|v| v == 0} vals = vals.each_cons(2).map {|a,b| b - a} layers << vals end layers.reverse!.each_cons(2).map {|diffs, vals| vals << diffs[-1] + vals[-1]} layers[-1][-1] end puts predictions.sum # Rest of algorithm here