Codigo de la caja

code.rb

def allpairs(num)
  num.to_s.chars.all?{|c| c.to_i%2==0}
end

def first_and_last_equals(num)
  chars=num.to_s.chars

  chars[0] == chars[-1]
end

def first_one_third_of_fifth(num)
  chars=num.to_s.chars
  chars[0].to_i == chars[4].to_i/3.0
end

def first_one_is_half_of_third(num)
  chars=num.to_s.chars
  chars[0].to_i== chars[2].to_i/2.0
end

def second_is_lowest(num)
  chars=num.to_s.chars.map{|x| x.to_i}

  min=chars.min
  return false unless min==chars[1]

  chars.delete_at(1)
  !chars.include?(min)
end

def last_one_is_fourth_less_fifth(num)
  chars=num.to_s.chars
  chars[-1].to_i==chars[3].to_i-chars[4].to_i
end

def check(num)
  allpairs(num) and first_and_last_equals(num) and first_one_third_of_fifth(num) and first_one_is_half_of_third(num) and second_is_lowest(num) and last_one_is_fourth_less_fifth(num)
end


num=200000

while num<888888 do
  num+=2
  if(check(num)) then
    p "Answer is #{num}"
  end

end