72 lines
1.6 KiB
Markdown
72 lines
1.6 KiB
Markdown
---
|
||
id: 5900f4021000cf542c50ff13
|
||
challengeType: 5
|
||
title: 'Problem 149: Searching for a maximum-sum subsequence'
|
||
---
|
||
|
||
## Description
|
||
<section id='description'>
|
||
Looking at the table below, it is easy to verify that the maximum possible sum of adjacent numbers in any direction (horizontal, vertical, diagonal or anti-diagonal) is 16 (= 8 + 7 + 1).
|
||
|
||
|
||
−25329−6513273−18−4 8
|
||
|
||
Now, let us repeat the search, but on a much larger scale:
|
||
|
||
First, generate four million pseudo-random numbers using a specific form of what is known as a "Lagged Fibonacci Generator":
|
||
|
||
For 1 ≤ k ≤ 55, sk = [100003 − 200003k + 300007k3] (modulo 1000000) − 500000.
|
||
For 56 ≤ k ≤ 4000000, sk = [sk−24 + sk−55 + 1000000] (modulo 1000000) − 500000.
|
||
|
||
Thus, s10 = −393027 and s100 = 86613.
|
||
|
||
The terms of s are then arranged in a 2000×2000 table, using the first 2000 numbers to fill the first row (sequentially), the next 2000 numbers to fill the second row, and so on.
|
||
|
||
Finally, find the greatest sum of (any number of) adjacent entries in any direction (horizontal, vertical, diagonal or anti-diagonal).
|
||
</section>
|
||
|
||
## Instructions
|
||
<section id='instructions'>
|
||
|
||
</section>
|
||
|
||
## Tests
|
||
<section id='tests'>
|
||
|
||
```yml
|
||
tests:
|
||
- text: <code>euler149()</code> should return 52852124.
|
||
testString: 'assert.strictEqual(euler149(), 52852124, "<code>euler149()</code> should return 52852124.");'
|
||
|
||
```
|
||
|
||
</section>
|
||
|
||
## Challenge Seed
|
||
<section id='challengeSeed'>
|
||
|
||
<div id='js-seed'>
|
||
|
||
```js
|
||
function euler149() {
|
||
// Good luck!
|
||
return true;
|
||
}
|
||
|
||
euler149();
|
||
```
|
||
|
||
</div>
|
||
|
||
|
||
|
||
</section>
|
||
|
||
## Solution
|
||
<section id='solution'>
|
||
|
||
```js
|
||
// solution required
|
||
```
|
||
</section>
|