"I have this code, you see... and it takes a couple mutable references into an array... how do I translate this into Rust?"

There is no one-size-fits-all answer to that question. The code may be correct in C or C++, but the Rust type system may give you one hell of a hard time proving that it is correct to the Rust type system's satisfaction... so you refactor your code completely, or you use integer indexes into arrays rather than references, or you use unsafe code...

I've written some amount of Rust code at this point. About half of the time, when I write a project in Rust, there comes a point at which I'm fighting with the type system. I feel like this should stop happening, at some point.