65 lines
2.5 KiB
Markdown
65 lines
2.5 KiB
Markdown
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---
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id: 5a23c84252665b21eecc7e1e
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title: Dot product
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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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Create a function, to compute the <b><a href="https://en.wikipedia.org/wiki/Dot product">dot product</a></b>, also known as the <b>scalar product</b> of two vectors.
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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>dotProduct</code> should be a function.
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testString: assert(typeof dotProduct == 'function', '<code>dotProduct</code> should be a function.');
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- text: <code>dotProduct([1, 3, -5], [4, -2, -1])</code> should return a number.
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testString: assert(typeof dotProduct([1, 3, -5], [4, -2, -1]) == 'number', '<code>dotProduct([1, 3, -5], [4, -2, -1])</code> should return a number.');
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- text: <code>dotProduct([1, 3, -5], [4, -2, -1])</code> should return <code>3</code>.
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testString: assert.equal(dotProduct([1, 3, -5], [4, -2, -1]), 3, '<code>dotProduct([1, 3, -5], [4, -2, -1])</code> should return <code>3</code>.');
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- text: <code>dotProduct([1, 2, 3, 4, 5], [6, 7, 8, 9, 10])</code> should return <code>130</code>.
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testString: assert.equal(dotProduct([1, 2, 3, 4, 5], [6, 7, 8, 9, 10]), 130, '<code>dotProduct([1, 2, 3, 4, 5], [6, 7, 8, 9, 10])</code> should return <code>130</code>.');
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- text: <code>dotProduct([5, 4, 3, 2], [7, 8, 9, 6])</code> should return <code>106</code>.
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testString: assert.equal(dotProduct([5, 4, 3, 2], [7, 8, 9, 6]), 106, '<code>dotProduct([5, 4, 3, 2], [7, 8, 9, 6])</code> should return <code>106</code>.');
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- text: <code>dotProduct([-5, 4, -3, 2], [-7, -8, 9, -6])</code> should return <code>-36</code>.
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testString: assert.equal(dotProduct([-5, 4, -3, 2], [-7, -8, 9, -6]), -36, '<code>dotProduct([-5, 4, -3, 2], [-7, -8, 9, -6])</code> should return <code>-36</code>.');
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- text: <code>dotProduct([17, 27, 34, 43, 15], [62, 73, 48, 95, 110])</code> should return <code>10392</code>.
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testString: assert.equal(dotProduct([17, 27, 34, 43, 15], [62, 73, 48, 95, 110]), 10392, '<code>dotProduct([17, 27, 34, 43, 15], [62, 73, 48, 95, 110])</code> should return <code>10392</code>.');
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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 dotProduct (ary1, ary2) {
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// Good luck!
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}
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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 dotProduct (ary1, ary2) {
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var dotprod = 0;
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for (var i = 0; i < ary1.length; i++)
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dotprod += ary1[i] * ary2[i];
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return dotprod;
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}
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```
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</section>
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