62 lines
1.0 KiB
Markdown
62 lines
1.0 KiB
Markdown
---
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id: 5900f4151000cf542c50ff28
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challengeType: 5
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title: 'Problem 169: Exploring the number of different ways a number can be expressed as a sum of powers of 2'
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---
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## Description
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<section id='description'>
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Define f(0)=1 and f(n) to be the number of different ways n can be expressed as a sum of integer powers of 2 using each power no more than twice.
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For example, f(10)=5 since there are five different ways to express 10:
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1 + 1 + 8
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1 + 1 + 4 + 41 + 1 + 2 + 2 + 4
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2 + 4 + 4
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2 + 8
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What is f(1025)?
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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>euler169()</code> should return 178653872807.
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testString: assert.strictEqual(euler169(), 178653872807, '<code>euler169()</code> should return 178653872807.');
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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 euler169() {
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// Good luck!
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return true;
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}
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euler169();
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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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// solution required
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```
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</section>
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