maybe you can use a list that from 0 to len(n) to represent the length

I figured it out in the end.

I like this kata because it taught me not to mutate the inputs, now i try keep this in mind when solving other kata.

It depends how did you create.

let arr = nums;
Won't work because changin arr will also change nums. It's because they are not primitive types of variables, they are reference types. you can have a research about it to understand better.

I have no idea how this works for the arrays with only one item in them.

Im so confused.
I made a new list and mutated that...didnt work.
So there is a way to remove the lowest number without changing the original list.
My only guess is u get the minimum number seperately and do something with it.