2018-10-10 22:03:03 +00:00
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---
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id: 5900f3fd1000cf542c50ff10
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2020-12-16 07:37:30 +00:00
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title: 问题145:有多少可逆数字低于十亿?
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2018-10-10 22:03:03 +00:00
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challengeType: 5
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videoUrl: ''
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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一些正整数n具有sum \[n + reverse(n)]完全由奇数(十进制)数字组成的属性。例如,36 + 63 = 99和409 + 904 = 1313.我们将这些数字称为可逆的;所以36,63,409和904是可逆的。 n或反向(n)中不允许前导零。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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有一千个可逆数字低于一千。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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有多少可逆数字低于十亿(109)?
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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# --hints--
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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`euler145()`应该返回608720。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert.strictEqual(euler145(), 608720);
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2018-10-10 22:03:03 +00:00
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2020-08-13 15:24:35 +00:00
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