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>
103 lines
1.9 KiB
Markdown
103 lines
1.9 KiB
Markdown
---
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id: 5a23c84252665b21eecc7e76
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title: 伽玛功能
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challengeType: 5
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videoUrl: ''
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dashedName: gamma-function
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---
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# --description--
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实现一个算法（或更多）来计算[Gamma](<https://en.wikipedia.org/wiki/Gamma function>) （$ \\ Gamma $）函数（仅在实际字段中）。 Gamma功能可以定义为：
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$ \\ Gamma（x）= \\ displaystyle \\ int_0 ^ \\ infty t ^ {x-1} e ^ { - t} dt $
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# --hints--
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`gamma`应该是一个功能。
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```js
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assert(typeof gamma == 'function');
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```
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`gamma("+tests[0]+")`应该返回一个数字。
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```js
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assert(typeof gamma(0.1) == 'number');
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```
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`gamma("+tests[0]+")`应该返回`"+results[0]+"` 。
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```js
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assert.equal(round(gamma(0.1)), round(9.513507698668736));
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```
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`gamma("+tests[1]+")`应该返回`"+results[1]+"` 。
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```js
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assert.equal(round(gamma(0.2)), round(4.590843711998803));
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```
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`gamma("+tests[2]+")`应该返回`"+results[2]+"` 。
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```js
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assert.equal(round(gamma(0.3)), round(2.9915689876875904));
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```
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`gamma("+tests[3]+")`应该返回`"+results[3]+"` 。
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```js
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assert.equal(round(gamma(0.4)), round(2.218159543757687));
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```
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`gamma("+tests[4]+")`应返回`"+results[4]+"` 。
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```js
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assert.equal(round(gamma(0.5)), round(1.7724538509055159));
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```
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# --seed--
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## --after-user-code--
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```js
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function round(x) {
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return Number(x).toPrecision(13);
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}
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```
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## --seed-contents--
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```js
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function gamma(x) {
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}
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```
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# --solutions--
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```js
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function gamma(x) {
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var p = [0.99999999999980993, 676.5203681218851, -1259.1392167224028,
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771.32342877765313, -176.61502916214059, 12.507343278686905,
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-0.13857109526572012, 9.9843695780195716e-6, 1.5056327351493116e-7
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];
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var g = 7;
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if (x < 0.5) {
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return Math.PI / (Math.sin(Math.PI * x) * gamma(1 - x));
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}
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x -= 1;
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var a = p[0];
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var t = x + g + 0.5;
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for (var i = 1; i < p.length; i++) {
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a += p[i] / (x + i);
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}
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var result=Math.sqrt(2 * Math.PI) * Math.pow(t, x + 0.5) * Math.exp(-t) * a;
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return result;
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}
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```
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