fix(curriculum): rework Project Euler 75 (#42066)

* fix: rework challenge to use argument in function

* fix: add solution

* fix: position block evenly between paragraphs
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gikf
2021-05-11 14:56:58 +02:00
committed by GitHub
parent 7a8d6b2504
commit 4260416ac3

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@ -16,29 +16,47 @@ It turns out that 12 cm is the smallest length of wire that can be bent to form
<strong>30 cm:</strong> (5,12,13)<br>
<strong>36 cm:</strong> (9,12,15)<br>
<strong>40 cm:</strong> (8,15,17)<br>
<strong>48 cm:</strong> (12,16,20)<br>
<strong>48 cm:</strong> (12,16,20)<br><br>
</div>
In contrast, some lengths of wire, like 20 cm, cannot be bent to form an integer sided right angle triangle, and other lengths allow more than one solution to be found; for example, using 120 cm it is possible to form exactly three different integer sided right angle triangles.
<div style='margin-left: 4em;'>
<strong>120 cm:</strong> (30,40,50), (20,48,52), (24,45,51)
<strong>120 cm:</strong> (30,40,50), (20,48,52), (24,45,51)<br><br>
</div>
Given that L is the length of the wire, for how many values of L ≤ 1,500,000 can exactly one integer sided right angle triangle be formed?
Given that L is the length of the wire, for how many values of L ≤ `n` can exactly one, integer sided right angle, triangle be formed?
# --hints--
`singularIntRightTriangles()` should return a number.
`singularIntRightTriangles(48)` should return a number.
```js
assert(typeof singularIntRightTriangles() === 'number');
assert(typeof singularIntRightTriangles(48) === 'number');
```
`singularIntRightTriangles()` should return 161667.
`singularIntRightTriangles(48)` should return `6`.
```js
assert.strictEqual(singularIntRightTriangles(), 161667);
assert.strictEqual(singularIntRightTriangles(48), 6);
```
`singularIntRightTriangles(700000)` should return `75783`.
```js
assert.strictEqual(singularIntRightTriangles(700000), 75783);
```
`singularIntRightTriangles(1000000)` should return `107876`.
```js
assert.strictEqual(singularIntRightTriangles(1000000), 107876);
```
`singularIntRightTriangles(1500000)` should return `161667`.
```js
assert.strictEqual(singularIntRightTriangles(1500000), 161667);
```
# --seed--
@ -46,16 +64,54 @@ assert.strictEqual(singularIntRightTriangles(), 161667);
## --seed-contents--
```js
function singularIntRightTriangles() {
function singularIntRightTriangles(n) {
return true;
}
singularIntRightTriangles();
singularIntRightTriangles(48);
```
# --solutions--
```js
// solution required
function singularIntRightTriangles(limit) {
function euclidFormula(m, n) {
return [m ** 2 - n ** 2, 2 * m * n, m ** 2 + n ** 2];
}
function gcd(numberA, numberB) {
if (numberB === 0) {
return numberA;
}
return gcd(numberB, numberA % numberB);
}
function notBothOdd(numberA, numberB) {
return (numberA + numberB) % 2 === 1;
}
function areCoprime(numberA, numberB) {
return gcd(numberA, numberB) === 1;
}
const trianglesWithPerimeter = new Array(limit + 1).fill(0);
const mLimit = Math.sqrt(limit / 2);
for (let m = 2; m < mLimit; m++) {
for (let n = 1; n < m; n++) {
if (notBothOdd(m, n) && areCoprime(m, n)) {
const [sideA, sideB, sideC] = euclidFormula(m, n);
const perimeter = sideA + sideB + sideC;
let curPerimeter = perimeter;
while (curPerimeter <= limit) {
trianglesWithPerimeter[curPerimeter]++;
curPerimeter += perimeter;
}
}
}
}
return trianglesWithPerimeter.filter(trianglesCount => trianglesCount === 1)
.length;
}
```