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

curriculum/challenges/japanese/10-coding-interview-prep/project-euler/problem-430-range-flips.md

@@ -0,0 +1,50 @@
+---
+id: 5900f51a1000cf542c51002d
+title: 'Problem 430: Range flips'
+challengeType: 5
+forumTopicId: 302101
+dashedName: problem-430-range-flips
+---
+
+# --description--
+
+$N$ disks are placed in a row, indexed 1 to $N$ from left to right.
+
+Each disk has a black side and white side. Initially all disks show their white side.
+
+At each turn, two, not necessarily distinct, integers $A$ and $B$ between 1 and $N$ (inclusive) are chosen uniformly at random. All disks with an index from $A$ to $B$ (inclusive) are flipped.
+
+The following example shows the case $N = 8$. At the first turn $A = 5$ and $B = 2$, and at the second turn $A = 4$ and $B = 6$.
+
+<img class="img-responsive center-block" alt="example for N = 8, with first turn A = 5 and B = 2, and second turn A = 4 and B = 6" src="https://cdn.freecodecamp.org/curriculum/project-euler/range-flips.gif" style="background-color: white; padding: 10px;" />
+
+Let $E(N, M)$ be the expected number of disks that show their white side after $M$ turns. We can verify that $E(3, 1) = \frac{10}{9}$, $E(3, 2) = \frac{5}{3}$, $E(10, 4) ≈ 5.157$ and $E(100, 10) ≈ 51.893$.
+
+Find $E({10}^{10}, 4000)$. Give your answer rounded to 2 decimal places behind the decimal point.
+
+# --hints--
+
+`rangeFlips()` should return `5000624921.38`.
+
+```js
+assert.strictEqual(rangeFlips(), 5000624921.38);
+```
+
+# --seed--
+
+## --seed-contents--
+
+```js
+function rangeFlips() {
+
+  return true;
+}
+
+rangeFlips();
+```
+
+# --solutions--
+
+```js
+// solution required
+```