Sum All Primes, working on my PC but failing tests

Back End Help
#1

Tell us what’s happening:

Hey all! I’m running this exact same code on my laptop, locally, and when I give it 977 I’m getting the correct output (73156), is this a memory issue? Hope there’s a fix! Thanks everyone!

Your code so far


function isPrime(num) {
  let count = 0;
  for (let i = 1; i < num+1; i++) {
    if (num % i === 0) {
      count++;
    }
    if (count > 2) {
      return false;
    }
  }
  return true;
}

function sumPrimes(num) {
  let sum = 0;
  for (let i = 2; i <= num; i++) {
    if (isPrime(i)) {
      sum += i;
      console.log(i);
    } 
  }
  return sum;
}

console.log(sumPrimes(977));

Your browser information:

User Agent is: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/75.0.3770.90 Chrome/75.0.3770.90 Safari/537.36.

Link to the challenge:
https://learn.freecodecamp.org/javascript-algorithms-and-data-structures/intermediate-algorithm-scripting/sum-all-primes/

#2

you may be triggering the infinite loop protection on the editor here, if your code takes too much to run it is stopped. you will need a more efficient code

#3

I see, I imagined it was something of the like
Thanks, I’ll try to make it better

#4

Alright, I’m kinda lost.
If you guys could point me in the right direction i’d be really grateful, I got told I should look into recursion but I’m not sure.

#5

both your loops check using i++ check till the number itself- it is a bit long like that. you could do a few searches online to see what you find out as algorithms

or, do you know that to check if 19 is prime you don’t need to check if it is divisible by 18, 15 or 10 - the highest number you need to check is 5 (which is the square root rounded up)

also I suggest the isPrime function loop starts at let i = 2 and return false as soon as it find something - there is no need for count variable, and you save an iteration for all numbers to check

1 Like