This can be done with Rust as well, using unsafe code block if absolutely necessary. And only those blocks have to be reviewed for footguns, as opposed to your

This can be done with Rust as well, using unsafe code block if absolutely necessary. And only those blocks have to be reviewed for footguns, as opposed to your entire C++ code. Also even a 10x speedup sounds much. In Rust, instead using .get_unchecked() (the C++ equivalent) instead of using .get() is typically only a neglegible improvement of a few percentage points in that particular loop or whatever.