feat(learn): python certification projects (#38216)

Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>
Co-authored-by: Kristofer Koishigawa <scissorsneedfoodtoo@gmail.com>
Co-authored-by: Beau Carnes <beaucarnes@gmail.com>

curriculum/challenges/english/10-coding-interview-prep/rosetta-code/hailstone-sequence.english.md

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+---
+title: Hailstone sequence
+id: 595608ff8bcd7a50bd490181
+challengeType: 5
+isHidden: false
+forumTopicId: 302279
+---
+
+## Description
+<section id='description'>
+The Hailstone sequence of numbers can be generated from a starting positive integer, <code>n</code> by:
+<ul>
+  <li>If <code>n</code> is <code>1</code> then the sequence ends</li>
+  <li>If <code>n</code> is <code>even</code> then the next <code>n</code> of the sequence <code>= n/2</code></li>
+  <li>If <code>n</code> is <code>odd</code> then the next <code>n</code> of the sequence <code>= (3 * n) + 1</code></li>
+</ul>
+The (unproven) <a href="https://en.wikipedia.org/wiki/Collatz conjecture" title="wp: Collatz conjecture" target="_blank">Collatz conjecture</a> is that the hailstone sequence for any starting number always terminates.
+The hailstone sequence is also known as hailstone numbers (because the values are usually subject to multiple descents and ascents like hailstones in a cloud), or as the Collatz sequence.
+</section>
+
+## Instructions
+<section id='instructions'>
+<ol>
+  <li>Create a routine to generate the hailstone sequence for a number</li>
+  <li>Use the routine to show that the hailstone sequence for the number 27 has 112 elements starting with <code>27, 82, 41, 124</code> and ending with <code>8, 4, 2, 1</code></li>
+  <li>Show the number less than 100,000 which has the longest hailstone sequence together with that sequence's length. (But don't show the actual sequence!)</li>
+</ol>
+<strong>See also:</strong>
+<ul>
+  <li><a href="https://xkcd.com/710" target="_blank">xkcd</a> (humourous).</li>
+</ul>
+</section>
+
+## Tests
+<section id='tests'>
+
+```yml
+tests:
+  - text: <code>hailstoneSequence</code> should be a function.
+    testString: assert(typeof hailstoneSequence === 'function');
+  - text: <code>hailstoneSequence()</code> should return <code>[[27,82,41,124,8,4,2,1], [351, 77031]]</code>
+    testString: assert.deepEqual(hailstoneSequence(), res);
+
+```
+
+</section>
+
+## Challenge Seed
+<section id='challengeSeed'>
+
+<div id='js-seed'>
+
+```js
+// noprotect
+function hailstoneSequence() {
+  const res = [];
+  // Good luck!
+
+  return res;
+}
+```
+
+</div>
+
+
+### After Test
+<div id='js-teardown'>
+
+```js
+const res = [[27, 82, 41, 124, 8, 4, 2, 1], [351, 77031]];
+```
+
+</div>
+
+</section>
+
+## Solution
+<section id='solution'>
+
+
+```js
+// noprotect
+function hailstoneSequence () {
+  const res = [];
+
+  function hailstone(n) {
+    const seq = [n];
+    while (n > 1) {
+      n = n % 2 ? 3 * n + 1 : n / 2;
+      seq.push(n);
+    }
+    return seq;
+  }
+
+  const h = hailstone(27);
+  const hLen = h.length;
+  res.push([...h.slice(0, 4), ...h.slice(hLen - 4, hLen)]);
+
+  let n = 0;
+  let max = 0;
+  for (let i = 100000; --i;) {
+    const seq = hailstone(i);
+    const sLen = seq.length;
+
+    if (sLen > max) {
+      n = i;
+      max = sLen;
+    }
+  }
+  res.push([max, n]);
+
+  return res;
+}
+
+```
+
+</section>