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

  // use std::iter::FromIterator;
  use std::collections::HashSet;

  fn hashset_from_str(string: &str) -> HashSet<char> {
    std::collections::HashSet::<_>::from_iter(string.to_lowercase().chars())
  }

  let rows = [
    hashset_from_str("qwertyuiop"),
    hashset_from_str("asdfghjkl"),
    hashset_from_str("zxcvbnm"),
  ];

  let mut result = vec![];

  for word in words {
    let word_set = hashset_from_str(&word);

    if rows.iter().any(|row| word_set.is_subset(row)) {
      result.push(word);
    }
  }

  result
}