freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-115-counting-block-combinations-ii.english.md

---
id: 5900f3df1000cf542c50fef1
challengeType: 5
title: 'Problem 115: Counting block combinations II'
---

## Description
<section id='description'>
NOTE: This is a more difficult version of Problem 114.
A row measuring n units in length has red blocks with a minimum length of m units placed on it, such that any two red blocks (which are allowed to be different lengths) are separated by at least one black square.
Let the fill-count function, F(m, n), represent the number of ways that a row can be filled.
For example, F(3, 29) = 673135 and F(3, 30) = 1089155.
That is, for m = 3, it can be seen that n = 30 is the smallest value for which the fill-count function first exceeds one million.
In the same way, for m = 10, it can be verified that F(10, 56) = 880711 and F(10, 57) = 1148904, so n = 57 is the least value for which the fill-count function first exceeds one million.
For m = 50, find the least value of n for which the fill-count function first exceeds one million.
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler115()</code> should return 168.
    testString: assert.strictEqual(euler115(), 168, '<code>euler115()</code> should return 168.');

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler115() {
  // Good luck!
  return true;
}

euler115();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```

</section>