45 lines
859 B
Crystal
45 lines
859 B
Crystal
|
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
|