80 lines
2.1 KiB
Markdown
80 lines
2.1 KiB
Markdown
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---
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id: 5
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localeTitle: 5900f3941000cf542c50fea7
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challengeType: 5
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title: 'Problem 40: Champernowne"s constant'
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---
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## Description
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<section id='description'>
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Una fracción decimal irracional se crea mediante la concatenación de los números enteros positivos:
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<span style='display: block; text-align: center;'>,12345678910 <b style='color: red;'>1</b> 112131415161718192021 ...</span>
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Se puede observar que el 12 <sup>de</sup> dígitos de la parte fraccionaria es de 1.
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Si <i>d <sub>n</sub></i> representa el <i><sup>enésimo</sup></i> dígitos de la parte fraccionaria , encuentra el valor de la siguiente expresión.
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<span style='display: block; text-align: center;'>d <sub>1</sub> × d <sub>10</sub> × d <sub>100</sub> × d <sub>1000</sub> × d <sub>10000</sub> × d <sub>100000</sub> × d <sub>1000000</sub></span>
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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>champernownesConstant(100)</code> debe devolver 5.
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testString: 'assert.strictEqual(champernownesConstant(100), 5, "<code>champernownesConstant(100)</code> should return 5.");'
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- text: <code>champernownesConstant(1000)</code> debe devolver 15.
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testString: 'assert.strictEqual(champernownesConstant(1000), 15, "<code>champernownesConstant(1000)</code> should return 15.");'
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- text: <code>champernownesConstant(1000000)</code> debe devolver 210.
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testString: 'assert.strictEqual(champernownesConstant(1000000), 210, "<code>champernownesConstant(1000000)</code> should return 210.");'
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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 champernownesConstant(n) {
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// Good luck!
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return true;
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}
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champernownesConstant(100);
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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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function champernownesConstant(n) {
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let fractionalPart = ";
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for (let i = 0; fractionalPart.length <= n; i++) {
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fractionalPart += i.toString();
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}
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let product = 1;
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for (let i = 0; i < n.toString().length; i++) {
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const index = 10 ** i;
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product *= parseInt(fractionalPart[index], 10);
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}
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return product;
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}
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```
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</section>
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