pub fn is_anagram(a: String, b: String) -> bool {
  // Both strings must have the same length otherwise they can't be anagrams.
  if a.len() != b.len() {
    return false;
  }

  // Sort both strings' characters so they're in alphabetical order.
  let mut a = a.chars().collect::<Vec<_>>();
  a.sort();

  let mut b = b.chars().collect::<Vec<_>>();
  b.sort();

  // And if they are equal, then they're anagrams.
  a == b
}

#[test]
fn test_valid_anagram() {
  let samples = [
    (("💖🌠banana", "an💖anab🌠"), true),
    (("anagram", "nagaram"), true),
    (("bats", "tabs"), true),
    (("rat", "cat"), false),
    (("bats", "bat"), false),
  ];

  for ((a, b), expected) in samples {
    assert_eq!(is_anagram(a.to_string(), b.to_string()), expected);
  }
}