That was the issue, thanks!

Did you try not mutating the input?

When I attempt to run my solution, I pass all the basic tests, but I'm experiencing some weird behavior in the random tests. For instance, one of the random inputs was []int{-448, -361, 859, 28, 406, -397, 396}. I failed the test and got this message:

Expected
    <[]int | len:7, cap:8>: [859, 396, -361, -448, -397, 28, 406]
to equal
    <[]int | len:7, cap:8>: [859, 406, 28, -448, -397, 406, 406]

The expected output doesn't seem to be correct since some of the original values are written over with duplicate values. Why is this happening, and how can I fix it?

One of the random tests had num = 0. My code would return an empty string in this case, but the expected output was just printing the word once. Is this expected behavior? I don't see it specified anywhere in the instructions or example tests.

gotta get that hydratation