I implemented simple (dumb) algorithm for finding the largest Collatz trajectory (see Collatz conjecture) for all numbers < 100,000,000 in Python, Rust and Elixir.
I benchmarked them with
time command, assuming boot time is negligible
(Python and Elixir need ~1 sec to boot before the calculation loop starts but their runtime is in hundreds of seconds anyway.
Rust program boots in couple of milliseconds.)