81 lines
2.2 KiB
Markdown
81 lines
2.2 KiB
Markdown
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# Secret Handshake
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Welcome to Secret Handshake on Exercism's Elixir Track.
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If you need help running the tests or submitting your code, check out `HELP.md`.
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If you get stuck on the exercise, check out `HINTS.md`, but try and solve it without using those first :)
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## Introduction
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You are starting a secret coding club with some friends and friends-of-friends.
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Not everyone knows each other, so you and your friends have decided to create a secret handshake that you can use to recognize that someone is a member.
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You don't want anyone who isn't in the know to be able to crack the code.
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You've designed the code so that one person says a number between 1 and 31, and the other person turns it into a series of actions.
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## Instructions
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Your task is to convert a number between 1 and 31 to a sequence of actions in the secret handshake.
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The sequence of actions is chosen by looking at the rightmost five digits of the number once it's been converted to binary.
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Start at the right-most digit and move left.
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The actions for each number place are:
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```plaintext
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00001 = wink
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00010 = double blink
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00100 = close your eyes
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01000 = jump
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10000 = Reverse the order of the operations in the secret handshake.
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```
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Let's use the number `9` as an example:
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- 9 in binary is `1001`.
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- The digit that is farthest to the right is 1, so the first action is `wink`.
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- Going left, the next digit is 0, so there is no double-blink.
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- Going left again, the next digit is 0, so you leave your eyes open.
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- Going left again, the next digit is 1, so you jump.
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That was the last digit, so the final code is:
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```plaintext
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wink, jump
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```
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Given the number 26, which is `11010` in binary, we get the following actions:
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- double blink
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- jump
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- reverse actions
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The secret handshake for 26 is therefore:
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```plaintext
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jump, double blink
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```
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~~~~exercism/note
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If you aren't sure what binary is or how it works, check out [this binary tutorial][intro-to-binary].
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[intro-to-binary]: https://medium.com/basecs/bits-bytes-building-with-binary-13cb4289aafa
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~~~~
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## Source
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### Created by
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- @DoggettCK
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### Contributed to by
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- @angelikatyborska
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- @Cohen-Carlisle
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- @devonestes
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- @mlopes
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- @neenjaw
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- @sotojuan
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### Based on
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Bert, in Mary Poppins - https://www.imdb.com/title/tt0058331/quotes/?item=qt0437047
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