chore(i18n,learn): processed translations (#44851)

curriculum/challenges/japanese/10-coding-interview-prep/rosetta-code/factorial.md

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+---
+id: 597b2b2a2702b44414742771
+title: Factorial
+challengeType: 5
+forumTopicId: 302263
+dashedName: factorial
+---
+
+# --description--
+
+Write a function to return the factorial of a number.
+
+Factorial of a number is given by:
+
+<pre><big>n! = n * (n-1) * (n-2) * ..... * 1</big>
+</pre>
+
+For example:
+
+<ul>
+  <li><code>3! = 3 * 2 * 1 = 6</code></li>
+  <li><code>4! = 4 * 3 * 2 * 1 = 24</code></li>
+</ul>
+
+**Note:** `0! = 1`
+
+# --hints--
+
+`factorial` should be a function.
+
+```js
+assert(typeof factorial === 'function');
+```
+
+`factorial(2)` should return a number.
+
+```js
+assert(typeof factorial(2) === 'number');
+```
+
+`factorial(3)` should return 6.
+
+```js
+assert.equal(factorial(3), 6);
+```
+
+`factorial(5)` should return 120.
+
+```js
+assert.equal(factorial(5), 120);
+```
+
+`factorial(10)` should return 3,628,800.
+
+```js
+assert.equal(factorial(10), 3628800);
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+function factorial(n) {
+
+}
+```
+
+# --solutions--
+
+```js
+function factorial(n) {
+  let sum = 1;
+  while (n > 1) {
+    sum *= n;
+    n--;
+  }
+  return sum;
+}
+```