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>
45 lines
1016 B
Markdown
45 lines
1016 B
Markdown
---
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id: 5900f50a1000cf542c51001c
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title: 'Problem 413: One-child Numbers'
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challengeType: 5
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forumTopicId: 302082
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dashedName: problem-413-one-child-numbers
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---
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# --description--
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We say that a d-digit positive number (no leading zeros) is a one-child number if exactly one of its sub-strings is divisible by d.
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For example, 5671 is a 4-digit one-child number. Among all its sub-strings 5, 6, 7, 1, 56, 67, 71, 567, 671 and 5671, only 56 is divisible by 4. Similarly, 104 is a 3-digit one-child number because only 0 is divisible by 3. 1132451 is a 7-digit one-child number because only 245 is divisible by 7.
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Let F(N) be the number of the one-child numbers less than N. We can verify that F(10) = 9, F(103) = 389 and F(107) = 277674.
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Find F(1019).
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# --hints--
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`euler413()` should return 3079418648040719.
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```js
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assert.strictEqual(euler413(), 3079418648040719);
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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 euler413() {
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return true;
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}
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euler413();
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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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