Great Kata!

Can the solution have O(n²) time complexity?

C translation (author gone)

Forgot that we can change everything to make it look good! Nice and Clean!

need a fresh perspective
Translation Dart

I would greatly recommend joining Codewars Discord and its #help-solve channel, because it is much easier to discuss all problems there. But generally your issue boils down to: if the first element is different from the second element, how would you tell which one of the two is an outlier?

What a suprise seeing you again hobovsky. Thanks for the explanation, but im struggling on how else to identify that it is the odd one out.

Your solution has a bug which fails in some specific scenarios:

Your function assumes that the unique value will never be at the first index, but in some test cases, the unique number can appear at the beginning. Because you only compare each element to the first one, you incorrectly return a duplicate value when the single different value is at position 0.

You need to consider cases where the unique value isn't always somewhere after the first repeated value. Review your approach for correctly identifying the unique number regardless of its position in the array.

Some time ago I created a browser extension for Codewars which tries to help confused users and explain them, in a spoiler-free way, why their solution does not pass tests. Maybe you would find it helpful?

Additionally, if you want to post code and keep indentation, you need to use code blocks.

Thanks! Big relief to finally be able to finish this and look at some other ways of doing it.

I added console.log('input = ', arr) at the beginning of your function and console.log('output = ', result) at the end, here is what I see:

input =  [ '', '', '', 'a', '', '' ]
output =  undefined

your function fails that tests case because your result variable is never assigned a value: the 3 consecutive ifs are not entered, then masterKey === [], so the loop is not entered either, so result remains undefined.

Hi, I would really appreciate some help with this as I have been working on it for days but can't pass it.
When I click Test, it passes, but when I Attempt it, it passes everything except 'should handle empty or spaces string'
with the message:
'Non-empty string in empty strings: expected undefined to equal 'a''
However when I test my function the log (including in the same screen as above) says it is returning a
Is there something obvious I'm missing?
I set up an if loop to test if there are any spaces in the array, which returns the array as a joined string with the spaces deleted if so. If not, it goes into the else loop which tests for the unique string.

Yes, you made a mistake. You print more than one test case in a single line and all of them look to you as a single, large test.

Add this at the beginning of your function: echo "\nNew test\n";

In what language?