Thanks for this brilliant kata

You're right - this solution has O(N) complexity but there is O(1) solution. In fact looks like the current set of tests doesn't allow such a solution to be passed.

It was a wonderful math puzzle. Thank you

Hey there! Thanks for trying it out! Glad you enjoyed it. Make sure you also check out the next one in the series. Cheers!

Thanks for this nice kata! Enjoyed solving it.

This first if condition is not needed here. If arr1 is empty, arr1.size() returns 0 and the second if condition is never executed. If arr2 is empty, for each statement is not executed and outArray is returned as an empty collection anyway.

I couldn't agree less. We don't know if we are allowed to switch containers that we already put on a stack earlier on. Specs are of low quality.

again example 1:

2 primes: 73 and 97

97 isn't a member of the source array, primary 59 is

What a masterpiece! Thanks, docgunthrop.

Really clever

The complexity of this solution is quadratic

In the worst case scenario (the required item is the last one in the array) it will be quadratic complexity

This is a real masterpiece, one of the best 8 kyu katas. My respect to the author

I don't agree with the commenters below. Usually I spend a lot of time trying to reveal the purpose of a task - but this wasn't the case here. The description and examples (especially the one with "CODEWARS" string) are good written and make the task pretty easy to grasp. Nice kata and good job, @DarkD1!

You call countPrimeDiv twice on each iteration loop. It can be avoided and calculated only once.