pub fn contains_duplicate(numbers: Vec<i32>) -> bool {
  // Uncomment FromIterator in Leetcode since they're using Rust Edition 2018.
  // Edition 2021 has this trait in its prelude.

  // use std::iter::FromIterator;
  std::collections::HashSet::<_>::from_iter(numbers.iter()).len()
    != numbers.len()
}