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
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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>30 cm:</strong> (5,12,13)<br>
<strong>36 cm:</strong> (9,12,15)<br> <strong>36 cm:</strong> (9,12,15)<br>
<strong>40 cm:</strong> (8,15,17)<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> </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. 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;'> <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> </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-- # --hints--
`singularIntRightTriangles()` should return a number. `singularIntRightTriangles(48)` should return a number.
```js ```js
assert(typeof singularIntRightTriangles() === 'number'); assert(typeof singularIntRightTriangles(48) === 'number');
``` ```
`singularIntRightTriangles()` should return 161667. `singularIntRightTriangles(48)` should return `6`.
```js ```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-- # --seed--
@ -46,16 +64,54 @@ assert.strictEqual(singularIntRightTriangles(), 161667);
## --seed-contents-- ## --seed-contents--
```js ```js
function singularIntRightTriangles() { function singularIntRightTriangles(n) {
return true; return true;
} }
singularIntRightTriangles(); singularIntRightTriangles(48);
``` ```
# --solutions-- # --solutions--
```js ```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;
}
``` ```