From 61713a5faad8fad679639a2ed8e8a305a8e22603 Mon Sep 17 00:00:00 2001 From: Danila Fedorin Date: Sun, 6 Dec 2020 21:35:13 -0800 Subject: [PATCH] Add say 7 solution. --- day7.cr | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 day7.cr diff --git a/day7.cr b/day7.cr new file mode 100644 index 0000000..6329e2f --- /dev/null +++ b/day7.cr @@ -0,0 +1,44 @@ +require "advent" + +INPUT = input(2020, 7).lines.map(&.chomp).map do |s| + data = s.match(/^([a-z ]+) bags contain (.*).$/).not_nil! + {data[1], data[2].split(", ").map(&.rchop(" bags").rchop(" bag")) } +end + +def build_graph(input) + gr = Graph(String).new + seen = Set(String).new + input.each do |i| + next if i[1] == ["no other"] + seen << i[0] + i[1].each do |to| + n, _, m = to.partition(" ") + n = n.to_i32 + gr.add_edge(i[0], m, n) + end + end + {seen, gr} +end + +def part1 + seen, gr = build_graph(INPUT) + seen.count do |s| + gr.find_path(s, "shiny gold") && s != "shiny gold" + end +end + +def count_bags(gr, current) + return 1 unless es = gr.@edges[current]? + 1 + es.sum do |e| + t, k = e + k * count_bags(gr, t) + end +end + +def part2 + seen, gr = build_graph(INPUT) + count_bags(gr, "shiny gold") - 1 +end + +puts part1 +puts part2