Challenge #187: Generate Prime Numbers

[arjanloogman]

This one was fun and fast!! Didn't have to peek or google on this one, adds to my confidence...

Spoiler

 

Regards,

Arjan Loogman 

[nitinsnow]

catching up.

[Carlithian]

A fun challenge that I used to teach someone how to make iterative macros 🙂 This is what we came up with

[jgomel]

Here's my solution which allows you to set up what maximum value you want to find prime numbers for (limited to 10k, but can be increased)

I essentially use an iterative macro within a macro. Solution below.

Spoiler

Start doesn't look like much, you just simply change the input to the maximum number you want.



The macro will then just generate all the numbers excluding 1 and send to the iterative macro


In the iterative macro the values will be looped through removing along the way the values that could be divided by the smallest integer availalbe.
The exception being when the integer and the lowest integer are the same, which are the prime numbers. Et Voila!

[Ruud]

Spoiler

Decided I make it slighty more efficient by skipping all even numbers and appending only numbers that are smaller than my starting number. Batched it on number and was good to go. Still super brute-force 😄

[lcrosby]

Nice simply idea to remove even numbers - I amended my solution to do the same (which doesn't use a macro and doesn't just compare smaller numbers) and it reduced the run time from 55 seconds to just under 10.

[Galouzis]

Yet another solution

[ADerbak]

I liked this one a lot! Didn't even use the input or an input tool 🙂

[nini]

My solution:

[jgomel]

Second solution posted, but optimized using an Iterative macro. The flow initial value can be updated to find more or less primary numbers.

Spoiler

Iterative macro details