2021-06-15 00:49:18 -07:00
|
|
|
|
---
|
|
|
|
|
id: 5900f3ec1000cf542c50fefe
|
2022-02-28 13:29:21 +05:30
|
|
|
|
title: 'Problema 127: abc-hit'
|
2021-06-15 00:49:18 -07:00
|
|
|
|
challengeType: 5
|
|
|
|
|
forumTopicId: 301754
|
|
|
|
|
dashedName: problem-127-abc-hits
|
|
|
|
|
---
|
|
|
|
|
|
|
|
|
|
# --description--
|
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
Il radicale di $n$, $rad(n)$, è il prodotto dei fattori primi distinti di $n$. Per esempio, $504 = 2^3 × 3^2 × 7$, quindi $rad(504) = 2 × 3 × 7 = 42$.
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
Definiamo la tripletta di numeri interi positivi (a, b, c) come un abc-hit se:
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
1. $MCD(a, b) = MCD(a, c) = MCD(b, c) = 1$
|
|
|
|
|
2. $a < b$
|
|
|
|
|
3. $a + b = c$
|
|
|
|
|
4. $rad(abc) < c$
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
Per esempio, (5, 27, 32) è un abc-hit poiché:
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
1. $MCD(5, 27) = MCD(5, 32) = MCD(27, 32) = 1$
|
|
|
|
|
2. $5 < 27$
|
|
|
|
|
3. $5 + 27 = 32$
|
|
|
|
|
4. $rad(4320) = 30 < 32$
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
Gli abc-hit sono piuttosto rari e ce ne sono solo trentuno per $c < 1000$, con $\sum{c} = 12523$.
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
Trova $\sum{c}$ per $c < 120000$.
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
|
|
|
|
# --hints--
|
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
`abcHits()` dovrebbe restituire `18407904`.
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
|
|
|
|
```js
|
2022-02-28 13:29:21 +05:30
|
|
|
|
assert.strictEqual(abcHits(), 18407904);
|
2021-06-15 00:49:18 -07:00
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
# --seed--
|
|
|
|
|
|
|
|
|
|
## --seed-contents--
|
|
|
|
|
|
|
|
|
|
```js
|
2022-02-28 13:29:21 +05:30
|
|
|
|
function abcHits() {
|
2021-06-15 00:49:18 -07:00
|
|
|
|
|
|
|
|
|
return true;
|
|
|
|
|
}
|
|
|
|
|
|
2022-02-28 13:29:21 +05:30
|
|
|
|
abcHits();
|
2021-06-15 00:49:18 -07:00
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
# --solutions--
|
|
|
|
|
|
|
|
|
|
```js
|
|
|
|
|
// solution required
|
|
|
|
|
```
|