60 lines
1.1 KiB
Markdown
60 lines
1.1 KiB
Markdown
---
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id: 5900f3fd1000cf542c50ff10
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challengeType: 5
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title: 'Problem 145: How many reversible numbers are there below one-billion?'
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---
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## Description
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<section id='description'>
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Some positive integers n have the property that the sum [ n + reverse(n) ] consists entirely of odd (decimal) digits. For instance, 36 + 63 = 99 and 409 + 904 = 1313. We will call such numbers reversible; so 36, 63, 409, and 904 are reversible. Leading zeroes are not allowed in either n or reverse(n).
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There are 120 reversible numbers below one-thousand.
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How many reversible numbers are there below one-billion (109)?
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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>euler145()</code> should return 608720.
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testString: assert.strictEqual(euler145(), 608720, '<code>euler145()</code> should return 608720.');
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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 euler145() {
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// Good luck!
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return true;
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}
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euler145();
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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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