3920b7c4ce
* Translate challenge subtitles and example challenge text to Spanish * Corrected errors in syntax and punctuation * Multiple corrections of it/s to its plus other grammar corrections * Correction and added paragraph to CSS Flex article * Corrected my own typo * Corrected capitalization, American spellings and typos
50 lines
1.2 KiB
Markdown
50 lines
1.2 KiB
Markdown
---
|
|
title: 10001st prime
|
|
---
|
|
## Problem 7: 10001st prime
|
|
### Method:
|
|
- A prime number is a number which is divided by 1 and itself.
|
|
- We can find a number is prime if it's not divisible by other prime numbers smaller than itself.
|
|
|
|
### Solution:
|
|
```js
|
|
function nthPrime(n) {
|
|
|
|
//Primes array which will store all the prime numbers
|
|
const primes = [2];
|
|
|
|
//Num is the number we want to check
|
|
let num = 3, isPrime = true;
|
|
|
|
//Looping until primes array is equal to n
|
|
while (primes.length < n){
|
|
|
|
//All the primes numbers of a number is always <= its square root
|
|
let max = Math.ceil(Math.sqrt(num));
|
|
|
|
for (let i = 0; primes[i] <= max; i++){
|
|
if (num % primes[i] == 0) {
|
|
|
|
//Looping till we find the prime
|
|
isPrime = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
//if Prime found, push it to the array
|
|
if (isPrime) primes.push(num);
|
|
isPrime = true;
|
|
|
|
//An optimization technique, since we know of all even numbers only 2 is a prime number, we can skip the rest
|
|
num+=2;
|
|
}
|
|
|
|
//Returning the last number
|
|
return primes[primes.length-1];
|
|
|
|
}
|
|
```
|
|
-[Run Code](https://repl.it/@ezioda004/Project-Euler-Problem-7-10001st-prime)
|
|
### References:
|
|
- [Wikipedia](https://en.wikipedia.org/wiki/Prime_number)
|