Rust translation kumited .

You don't have flatten, but you can easily replace it with flat_map:

let a = [vec![1, 3, 5], vec![7, 9]];
// let flat = a.iter().flatten().collect::<Vec<_>>();
let flat = a.iter().flat_map(|x| x).collect::<Vec<_>>();
println!("{:?}", flat);

Yes, Rust.

The first 2 tests in basic_tests_dist are duplicates of one another.

fn basic_tests_dist(){
dotest1(144.0, 0.3, 311.83146449201496);
dotest1(144.0, 0.3, 311.83146449201496);

In the random test cases for Rust, the following line appears:

assert_eq!(remove_duplicate_words(&r), remove_duplicate_words(&r));

This line doesn't test anything. It should read instead:

assert_eq!(remove_duplicate_words(&r), solution(&r));