It's a nice xor swap, but I think you reversed your list twice. And xor swapping with x=y=2 is likely not ideal. Seems like exactly what I'd do in an interview too :p
> The XOR-swap trick is an example of coders being too clever for their own good. Here, it gradually poisons the RC4 permutation with zeroes, until eventually the plaintext is just passed along in the clear.
But apparently some people can just write it all out on a whiteboard in one go.