Project Euler - Problem 3: Largest prime factor

JavaScript
1

Tell us what’s happening:
Describe your issue in detail here.
my code is running well but i can’t pass the challenge
why?
Your code so far

function largestPrimeFactor(number) {
  let n = 0;
  let s = true
  for(let i = 2; i < number; i++){
    if(number % i == 0){
      s = false
      n = number / i
      break;
    }
    } 
     if(s == false){
       largestPrimeFactor(n)
     }else{
       console.log(number)
       return number
     }
    
  }

largestPrimeFactor(13195);

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Challenge: Project Euler - Problem 3: Largest prime factor

Link to the challenge:

2

Are you failing on the last test?

:largestPrimeFactor(600851475143) should return 6857.

4

the last 3 for some reason
no idea why
it should work

5

Edit: I think if you change the last line to pass 8 to your code you can probably log what is happening.

But basically, for 8, you should get 2 back.

As for the bigger numbers you need a more efficient algorithm probably.

6

Your recursive case has no return value.

7

no. it’s giving 2
i tried every single number in the tests
i even tried it in vs code

8

it does in the last not here you can check it out try every number and it should log it out then it should return it

9

No. Your base case has a return value. But since your recursive case has no return value, that doesn’t get propegated up the call stack and you are returning ‘undefined’.

1 Like
10

ok. i will try it now

11

what should i do here? :confused:

12

Literally, add a return statement in the recursive case, right where I highlighted.

13

yeah you are right it is returning undefined
thank you
what do you think i should do here?
is my code invalid?
or can i fix it?
what should i return there?

14

Did you try this yet?

15

i tried that but what should i return?
i tried to return number and n and it’s still the same

16

you should return your function call.

without it the whole recursion won’t work

1 Like
17

oh ok
i just tried that and it returned another number :cactus:
i think my code needs more work
thank you sir

18

I was able to pass the tests with your code by adding literaaly one keyword to it.

I am not sure if your code needs some huge refactoring

1 Like
19

oh ok…
can you tell me what it is?
i won’t look at it now
im going to take a little break then try again
but if i wasn’t able to find what it is i will look here XD

20

You literally only need to add the return keyword.

1 Like
21

yeah, look at the above. I do not know how to give more hints and not to give working solution. :upside_down_face:

1 Like