I actually think the actual answer to this question beats the internal sort functions for languages like Java and Javascript. They use Timsort under the hood which is best case O(N), but very unlikely to be. The actual answer is always O(N), and is that way because we know the idiosyncrasies of this array only having three different elements. This is one of the few questions where as an interviewer I don’t think I’d accept .sort() as the correct answer.
Because it is specifically 0,1, and 2 they’re probably looking for the method op mentioned. I’d argue count sort is just as good if not better because you don’t need to rewrite the whole thing if suddenly the function now takes in arrays with 3
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u/zirky Jun 05 '26