advent-of-code/2015/day-17/main.rb

65 lines
1.5 KiB
Ruby
Executable File

#!/usr/bin/env ruby
# frozen_string_literal: true
require "pathname"
require "set"
Container = Struct.new(:id, :cap)
# dumps result of previous solution to avoid recomputing
def memo(file)
dump_path = "#{file.basename}.rbdump"
if File.exist?(dump_path)
File.open(dump_path, "rb") { |df| Marshal.load(df) }
else
File.open(dump_path, "wb") do |dumpfile|
result = yield
dumpfile.write(Marshal.dump(result))
result
end
end
end
# quite inefficient, probably needs a DP solution
def combinations(amount, containers, stack = [], results = Set[])
stack_sum = stack.sum { |x| x.cap }
if stack_sum > amount
return results
elsif stack_sum == amount
results.add(stack.dup)
return results
end
return results if containers.empty?
containers.each_with_index do |container, idx|
combinations(amount, containers[(idx+1)..], [*stack, container], results)
end
combinations(amount, containers[1..], [], results)
end
def main(amount, file_paths)
amount = amount.to_i
file_paths.each do |file_path|
puts "Files: #{file_path}"
containers = file_path.each_line.with_index.map { |x, i| Container.new(i, x.to_i) }.freeze
result = memo(file_path) { combinations(amount, containers) }
solution1 = result.size
puts " Solution 1: #{solution1}"
solution2 = result.min_by { |x| x.size }.size
.then { |mincomb| result.select { |x| x.size == mincomb } }
.size
puts " Solution 2: #{solution2}"
end
end
main(ARGV[0], ARGV[1..].map { |x| Pathname(x) })