def range(s)
  n1, n2 = s.split('-')
  return n1.to_i .. n2.to_i
end

def read_pairs(filename)
  retval = []
  File.open(filename) do |file|
    file.readlines.each do |line|
      elf1, elf2 = line.split(',')
      retval << [range(elf1), range(elf2)]
    end
  end
  return retval
end

def range_included(r1, r2)
  return (r2.include?(r1.first) && r2.include?(r1.last)) || (r1.include?(r2.first) && r1.include?(r2.last))
end

def range_overlaps(r1, r2)
  return (r2.include?(r1.first) || r2.include?(r1.last)) || (r1.include?(r2.first) || r1.include?(r2.last))
end

def part1(filename)
  read_pairs(filename).map { |pairs|
    range_included(pairs[0], pairs[1])
  }.select { |x| x }.count
end

def part2(filename)
  read_pairs(filename).map { |pairs|
    range_overlaps(pairs[0], pairs[1])
  }.select { |x| x }.count

end