6cfd0fc503
* fix: improve Project Euler descriptions and test case Improve formatting of Project Euler test descriptions. Also add poker hands array and new test case for problem 54 * feat: add typeof tests and gave functions proper names for first 100 challenges * fix: continue fixing test descriptions and adding "before test" sections * fix: address review comments * fix: adjust grids in 18 and 67 and fix some text that reference files rather than the given arrays * fix: implement bug fixes and improvements from review * fix: remove console.log statements from seed and solution
89 lines
1.6 KiB
Markdown
89 lines
1.6 KiB
Markdown
---
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id: 5900f3731000cf542c50fe86
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challengeType: 5
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title: 'Problem 7: 10001st prime'
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forumTopicId: 302182
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---
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## Description
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<section id='description'>
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By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.
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What is the `n`th prime number?
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>nthPrime(6)</code> should return a number.
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testString: assert(typeof nthPrime(6) === 'number');
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- text: <code>nthPrime(6)</code> should return 13.
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testString: assert.strictEqual(nthPrime(6), 13);
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- text: <code>nthPrime(10)</code> should return 29.
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testString: assert.strictEqual(nthPrime(10), 29);
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- text: <code>nthPrime(100)</code> should return 541.
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testString: assert.strictEqual(nthPrime(100), 541);
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- text: <code>nthPrime(1000)</code> should return 7919.
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testString: assert.strictEqual(nthPrime(1000), 7919);
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- text: <code>nthPrime(10001)</code> should return 104743.
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testString: assert.strictEqual(nthPrime(10001), 104743);
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='js-seed'>
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```js
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function nthPrime(n) {
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// Good luck!
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return true;
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}
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nthPrime(10001);
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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const nthPrime = n => {
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let pN = 2;
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let step = 0;
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while (step < n) {
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let isPrime = true;
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let rootN = Math.sqrt(pN);
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for (let i = 2; i <= rootN; i++) {
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if (!(pN % i)) {
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isPrime = false;
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break;
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}
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}
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isPrime ? step++ : '';
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pN++;
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}
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return pN - 1;
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}
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```
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</section>
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