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Solving ROT13 Algorithm logic in Ruby
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| #!/usr/bin/env ruby | |
| str = "Jul qvq gur puvpxra pebff gur ebnq?" | |
| def rot13(secret_messages) | |
| upcase_alphabet = ("A".."Z").to_a | |
| downcase_alphabet = ("a".."z").to_a | |
| upcase_rot13 = [] | |
| upcase_length = upcase_alphabet.length | |
| downcase_length = downcase_alphabet.length | |
| upcase_alphabet.each_with_index do |c, i| | |
| if (i + 13) >= upcase_length | |
| upcase_rot13 << upcase_alphabet[(i + 13) - upcase_length] | |
| else | |
| upcase_rot13 << upcase_alphabet[(i + 13)] | |
| end | |
| end | |
| downcase_rot13 = [] | |
| downcase_alphabet.each_with_index do |c, i| | |
| if (i + 13) >= downcase_length | |
| downcase_rot13 << downcase_alphabet[(i + 13) - downcase_length] | |
| else | |
| downcase_rot13 << downcase_alphabet[(i + 13)] | |
| end | |
| end | |
| joined_alphabet = upcase_alphabet + downcase_alphabet | |
| joined_rot13 = upcase_rot13 + downcase_rot13 | |
| decrypted_messages = [] | |
| secret_messages.each do |str| | |
| tmp_result = [] | |
| str.each_char do |c| | |
| if /[A-Za-z]/.match c | |
| tmp_result << joined_rot13[joined_alphabet.find_index(c)] | |
| else | |
| tmp_result << c | |
| end | |
| end | |
| decrypted_messages << tmp_result | |
| end | |
| decrypted_messages | |
| end | |
| rot13(str) |
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