58 lines
1.5 KiB
Markdown
58 lines
1.5 KiB
Markdown
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# Collatz Conjecture
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The Collatz Conjecture or 3x+1 problem can be summarized as follows:
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Take any positive integer n. If n is even, divide n by 2 to get n / 2. If n is
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odd, multiply n by 3 and add 1 to get 3n + 1. Repeat the process indefinitely.
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The conjecture states that no matter which number you start with, you will
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always reach 1 eventually.
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Given a number n, return the number of steps required to reach 1.
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## Examples
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Starting with n = 12, the steps would be as follows:
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0. 12
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1. 6
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2. 3
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3. 10
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4. 5
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5. 16
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6. 8
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7. 4
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8. 2
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9. 1
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Resulting in 9 steps. So for input n = 12, the return value would be 9.
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* * * *
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For installation and learning resources, refer to the
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[exercism help page](http://exercism.io/languages/ruby).
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For running the tests provided, you will need the Minitest gem. Open a
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terminal window and run the following command to install minitest:
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gem install minitest
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If you would like color output, you can `require 'minitest/pride'` in
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the test file, or note the alternative instruction, below, for running
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the test file.
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Run the tests from the exercise directory using the following command:
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ruby collatz_conjecture_test.rb
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To include color from the command line:
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ruby -r minitest/pride collatz_conjecture_test.rb
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## Source
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An unsolved problem in mathematics named after mathematician Lothar Collatz [https://en.wikipedia.org/wiki/3x_%2B_1_problem](https://en.wikipedia.org/wiki/3x_%2B_1_problem)
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## Submitting Incomplete Solutions
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It's possible to submit an incomplete solution so you can see how others have completed the exercise.
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