Solution for 99minds to find Sum of sizes of directories less than 100000

99minds-directory-size.rb

require 'open-uri'
input = URI.open("https://gist.githubusercontent.com/ronakjain90/3dcfef6a752f77b3e8202ad9844195ae/raw/599eaaeec9f47b70a44da3454a731fee639efff3/input.txt").readlines

current_directory = []
directories = Hash.new { |h, k| h[k] = 0 }

input
  .map(&:chomp)
  .map(&:split)
  .each do |line|
    case line
    in ['$', 'cd', '..']
      current_directory.pop
    in ['$', 'cd', dir]
      current_directory << dir
    in [size, filename]
      current_directory.length.times do |a|
        directories[current_directory[0..a]] += size.to_i
      end
    end
  end

result = directories.select { |h,size| size <= 100000 }
p 'All directories less than 100000'
p result.keys
p "Sum of sizes of directories less than 100000 -> #{result.values.sum}"