freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-309-integer-ladders.md

---
id: 5900f4a11000cf542c50ffb4
title: 'Problem 309: Integer Ladders'
challengeType: 5
forumTopicId: 301963
dashedName: problem-309-integer-ladders
---

# --description--

In the classic "Crossing Ladders" problem, we are given the lengths x and y of two ladders resting on the opposite walls of a narrow, level street. We are also given the height h above the street where the two ladders cross and we are asked to find the width of the street (w).

Here, we are only concerned with instances where all four variables are positive integers. For example, if x = 70, y = 119 and h = 30, we can calculate that w = 56.

In fact, for integer values x, y, h and 0 < x < y < 200, there are only five triplets (x,y,h) producing integer solutions for w: (70, 119, 30), (74, 182, 21), (87, 105, 35), (100, 116, 35) and (119, 175, 40).

For integer values x, y, h and 0 < x < y < 1 000 000, how many triplets (x,y,h) produce integer solutions for w?

# --hints--

`euler309()` should return 210139.

```js
assert.strictEqual(euler309(), 210139);
```

# --seed--

## --seed-contents--

```js
function euler309() {

  return true;
}

euler309();
```

# --solutions--

```js
// solution required
```