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---
id: 5900f3ab1000cf542c50febe
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title: 'Problema 63: Conteggio cifre potenti'
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challengeType: 5
forumTopicId: 302175
dashedName: problem-63-powerful-digit-counts
---
# --description--
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Il numero a 5 cifre, 16807 = 7< sup > 5< / sup > , è anche una quinta potenza. Analogamente, il numero a 9 cifre, 134217728 = 8< sup > 9< / sup > , è una nona potenza.
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Completa la funzione in modo che restituisca quanti interi positivi siano di lunghezza `n` e `n` ma potenza.
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# --hints--
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`powerfulDigitCounts(1)` dovrebbe restituire un numero.
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```js
assert(typeof powerfulDigitCounts(1) === 'number');
```
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`powerfulDigitCounts(1)` dovrebbe restituire `9` .
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```js
assert.strictEqual(powerfulDigitCounts(1), 9);
```
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`powerfulDigitCounts(2)` dovrebbe restituire `6` .
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```js
assert.strictEqual(powerfulDigitCounts(2), 6);
```
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`powerfulDigitCounts(3)` dovrebbe restituire `5` .
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```js
assert.strictEqual(powerfulDigitCounts(3), 5);
```
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`powerfulDigitCounts(4)` dovrebbe restituire `4` .
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```js
assert.strictEqual(powerfulDigitCounts(4), 4);
```
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`powerfulDigitCounts(5)` dovrebbe restituire `3` .
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```js
assert.strictEqual(powerfulDigitCounts(5), 3);
```
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`powerfulDigitCounts(6)` dovrebbe restituire `3` .
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```js
assert.strictEqual(powerfulDigitCounts(6), 3);
```
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`powerfulDigitCounts(7)` dovrebbe restituire `2` .
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```js
assert.strictEqual(powerfulDigitCounts(7), 2);
```
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`powerfulDigitCounts(8)` dovrebbe restituire `2` .
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```js
assert.strictEqual(powerfulDigitCounts(8), 2);
```
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`powerfulDigitCounts(10)` dovrebbe restituire `2` .
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```js
assert.strictEqual(powerfulDigitCounts(10), 2);
```
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`powerfulDigitCounts(21)` dovrebbe restituire `1` .
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```js
assert.strictEqual(powerfulDigitCounts(21), 1);
```
# --seed--
## --seed-contents--
```js
function powerfulDigitCounts(n) {
return true;
}
powerfulDigitCounts(1);
```
# --solutions--
```js
function powerfulDigitCounts(n) {
function countDigits(num) {
let counter = 0;
while (num > 0) {
num = Math.floor(num / 10);
counter++;
}
return counter;
}
let numbersCount = 0;
let curNum = 1;
while (curNum < 10 ) {
let power = n;
if (power === countDigits(curNum ** power)) {
numbersCount++;
}
curNum++;
}
return numbersCount;
}
```