2021-06-15 07:49:18 +00:00
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---
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id: 5900f36f1000cf542c50fe82
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2021-07-29 16:41:44 +00:00
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title: 'Problema 3: il più grande fattore primo'
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2021-06-15 07:49:18 +00:00
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challengeType: 5
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forumTopicId: 301952
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dashedName: problem-3-largest-prime-factor
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---
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# --description--
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2021-07-29 16:41:44 +00:00
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I fattori primi di 13195 sono 5, 7, 13 e 29.
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2021-06-15 07:49:18 +00:00
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2021-07-29 16:41:44 +00:00
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Qual è il fattore primo più grande del `number` dato?
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2021-06-15 07:49:18 +00:00
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# --hints--
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(2)` dovrebbe restituire un numero.
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2021-06-15 07:49:18 +00:00
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```js
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assert(typeof largestPrimeFactor(2) === 'number');
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(2)` dovrebbe restituire 2.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(2), 2);
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(3)` dovrebbe restituire 3.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(3), 3);
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(5)` dovrebbe restituire 5.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(5), 5);
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(7)` dovrebbe restituire 7.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(7), 7);
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(8)` dovrebbe restituire 2.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(8), 2);
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(13195)` dovrebbe restituire 29.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(13195), 29);
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```
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2021-07-29 16:41:44 +00:00
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`largestPrimeFactor(600851475143)` dovrebbe restituire 6857.
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2021-06-15 07:49:18 +00:00
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```js
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assert.strictEqual(largestPrimeFactor(600851475143), 6857);
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```
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# --seed--
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## --seed-contents--
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```js
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function largestPrimeFactor(number) {
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return true;
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}
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largestPrimeFactor(13195);
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```
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# --solutions--
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```js
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const largestPrimeFactor = (number) => {
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let largestFactor = number;
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for (let i = 2; i <= Math.sqrt(largestFactor); i++) {
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if (!(largestFactor % i)) {
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let factor = largestFactor / i;
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let candidate = largestPrimeFactor(factor);
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return i > candidate ? i : candidate;
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}
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}
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return largestFactor;
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}
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```
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