def rot13(secret_messages)

return secret_messages.map {|d| 
    ans = ""
    for i in(0...d.length)
        ans.insert(i,helper(d[i]))
    end
    ans
    }

end

def helper(ch) alpb = "abcdefghijklmnopqrstuvwxyz" i = ch.downcase.ord - 'a'.ord return i > 25 || i < 0 ? ch : ch.ord >= 65 && ch.ord <=90 ? alpb[(i + 13)%26].upcase : alpb[(i + 13)%26] end