Some solutions for the julia path

julia/collatz-conjecture/.exercism/config.json

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+{
+  "authors": [
+    "SaschaMann"
+  ],
+  "contributors": [
+    "guilhermebodin"
+  ],
+  "files": {
+    "solution": [
+      "collatz-conjecture.jl"
+    ],
+    "test": [
+      "runtests.jl"
+    ],
+    "example": [
+      ".meta/example.jl"
+    ]
+  },
+  "blurb": "Calculate the number of steps to reach 1 using the Collatz conjecture.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/Collatz_conjecture"
+}

julia/collatz-conjecture/.exercism/metadata.json

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+{"track":"julia","exercise":"collatz-conjecture","id":"3beda5faa27740749db53e30351afca0","url":"https://exercism.org/tracks/julia/exercises/collatz-conjecture","handle":"Kimawari","is_requester":true,"auto_approve":false}

julia/collatz-conjecture/HELP.md

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+# Help
+
+## Running the tests
+
+To run the tests, run this command from within the exercise directory:
+
+```bash
+$ julia runtests.jl
+```
+
+## Submitting your solution
+
+You can submit your solution using the `exercism submit collatz-conjecture.jl` command.
+This command will upload your solution to the Exercism website and print the solution page's URL.
+
+It's possible to submit an incomplete solution which allows you to:
+
+- See how others have completed the exercise
+- Request help from a mentor
+
+## Need to get help?
+
+If you'd like help solving the exercise, check the following pages:
+
+- The [Julia track's documentation](https://exercism.org/docs/tracks/julia)
+- The [Julia track's programming category on the forum](https://forum.exercism.org/c/programming/julia)
+- [Exercism's programming category on the forum](https://forum.exercism.org/c/programming/5)
+- The [Frequently Asked Questions](https://exercism.org/docs/using/faqs)
+
+Should those resources not suffice, you could submit your (incomplete) solution to request mentoring.
+
+To get help if you're having trouble, we recommend that you submit your code and request mentoring :)
+
+If you don't want to do that for whatever reason, then you can find the wider Julia community channels [here](https://julialang.org/community/).

julia/collatz-conjecture/README.md

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+# Collatz Conjecture
+
+Welcome to Collatz Conjecture on Exercism's Julia Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Introduction
+
+One evening, you stumbled upon an old notebook filled with cryptic scribbles, as though someone had been obsessively chasing an idea.
+On one page, a single question stood out: **Can every number find its way to 1?**
+It was tied to something called the **Collatz Conjecture**, a puzzle that has baffled thinkers for decades.
+
+The rules were deceptively simple.
+Pick any positive integer.
+
+- If it's even, divide it by 2.
+- If it's odd, multiply it by 3 and add 1.
+
+Then, repeat these steps with the result, continuing indefinitely.
+
+Curious, you picked number 12 to test and began the journey:
+
+12 ➜ 6 ➜ 3 ➜ 10 ➜ 5 ➜ 16 ➜ 8 ➜ 4 ➜ 2 ➜ 1
+
+Counting from the second number (6), it took 9 steps to reach 1, and each time the rules repeated, the number kept changing.
+At first, the sequence seemed unpredictable — jumping up, down, and all over.
+Yet, the conjecture claims that no matter the starting number, we'll always end at 1.
+
+It was fascinating, but also puzzling.
+Why does this always seem to work?
+Could there be a number where the process breaks down, looping forever or escaping into infinity?
+The notebook suggested solving this could reveal something profound — and with it, fame, [fortune][collatz-prize], and a place in history awaits whoever could unlock its secrets.
+
+[collatz-prize]: https://mathprize.net/posts/collatz-conjecture/
+
+## Instructions
+
+Given a positive integer, return the number of steps it takes to reach 1 according to the rules of the Collatz Conjecture.
+
+## Source
+
+### Created by
+
+- @SaschaMann
+
+### Contributed to by
+
+- @guilhermebodin
+
+### Based on
+
+Wikipedia - https://en.wikipedia.org/wiki/Collatz_conjecture

julia/collatz-conjecture/collatz-conjecture.jl

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+function is_even(n::Int)
+    return n % 2 == 0
+end
+
+function is_odd(n::Int)
+    return n % 2 != 0
+end
+
+function collatz_steps(n::Int)
+    if n <= 0
+        throw(DomainError("Input must be a positive integer."))
+    end
+    steps = 0
+    while n != 1
+        if is_even(n)
+            n ÷= 2
+        else
+            n = 3 * n + 1
+        end
+        steps += 1
+    end
+    return steps
+end

julia/collatz-conjecture/runtests.jl

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+using Test
+
+include("collatz-conjecture.jl")
+
+@testset verbose = true "tests" begin
+    # canonical data
+    @testset "Canonical data" begin
+        @test collatz_steps(1) == 0
+        @test collatz_steps(16) == 4
+        @test collatz_steps(12) == 9
+        @test collatz_steps(1000000) == 152
+        @test_throws DomainError collatz_steps(0)
+        @test_throws DomainError collatz_steps(-15)
+    end
+end