ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
43 lines
644 B
Markdown
43 lines
644 B
Markdown
---
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id: 5900f5041000cf542c510016
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title: 问题407：幂等元素
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challengeType: 5
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videoUrl: ''
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dashedName: problem-407-idempotents
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---
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# --description--
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如果我们计算a2 mod 6为0≤a≤5，我们得到：0,1,4,3,4,1。
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a2≡amod 6的最大值为4.让我们将M（n）称为a <n的最大值，使得a2≡a（mod n）。所以M（6）= 4。
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找ΣM（n）为1≤n≤107。
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# --hints--
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`euler407()`应该返回39782849136421。
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```js
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assert.strictEqual(euler407(), 39782849136421);
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```
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# --seed--
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## --seed-contents--
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```js
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function euler407() {
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return true;
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}
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euler407();
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```
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# --solutions--
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```js
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// solution required
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```
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