89 lines
2.6 KiB
Markdown
89 lines
2.6 KiB
Markdown
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---
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id: ae9defd7acaf69703ab432ea
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title: Smallest Common Multiple
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isRequired: true
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challengeType: 5
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---
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## Description
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<section id='description'>
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Find the smallest common multiple of the provided parameters that can be evenly divided by both, as well as by all sequential numbers in the range between these parameters.
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The range will be an array of two numbers that will not necessarily be in numerical order.
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For example, if given 1 and 3, find the smallest common multiple of both 1 and 3 that is also evenly divisible by all numbers <em>between</em> 1 and 3. The answer here would be 6.
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Remember to use <a href='http://forum.freecodecamp.org/t/how-to-get-help-when-you-are-stuck/19514' target='_blank'>Read-Search-Ask</a> if you get stuck. Try to pair program. Write your own code.
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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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- text: '<code>smallestCommons([1, 5])</code> should return a number.'
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testString: 'assert.deepEqual(typeof smallestCommons([1, 5]), "number", "<code>smallestCommons([1, 5])</code> should return a number.");'
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- text: '<code>smallestCommons([1, 5])</code> should return 60.'
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testString: 'assert.deepEqual(smallestCommons([1, 5]), 60, "<code>smallestCommons([1, 5])</code> should return 60.");'
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- text: '<code>smallestCommons([5, 1])</code> should return 60.'
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testString: 'assert.deepEqual(smallestCommons([5, 1]), 60, "<code>smallestCommons([5, 1])</code> should return 60.");'
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- text: '<code>smallestCommons([2, 10])</code> should return 2520.'
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testString: 'assert.deepEqual(smallestCommons([2, 10]), 2520, "<code>smallestCommons([2, 10])</code> should return 2520.");'
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- text: '<code>smallestCommons([1, 13])</code> should return 360360.'
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testString: 'assert.deepEqual(smallestCommons([1, 13]), 360360, "<code>smallestCommons([1, 13])</code> should return 360360.");'
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- text: '<code>smallestCommons([23, 18])</code> should return 6056820.'
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testString: 'assert.deepEqual(smallestCommons([23, 18]), 6056820, "<code>smallestCommons([23, 18])</code> should return 6056820.");'
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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 smallestCommons(arr) {
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return arr;
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}
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smallestCommons([1,5]);
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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 gcd(a, b) {
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while (b !== 0) {
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a = [b, b = a % b][0];
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}
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return a;
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}
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function lcm(a, b) {
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return (a * b) / gcd(a, b);
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}
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function smallestCommons(arr) {
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arr.sort(function(a,b) {return a-b;});
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var rng = [];
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for (var i = arr[0]; i <= arr[1]; i++) {
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rng.push(i);
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}
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return rng.reduce(lcm);
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}
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```
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</section>
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