content: // https://leetcode.com/problems/valid-word
  // T: O(N)
  // S: O(1)
  
  import java.util.Set;
  
  public class ValidWord {
      private static final Set<Character> VOWELS = Set.of('a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U');
  
      public boolean isValid(String word) {
          return word.length() >= 3 && isAlphaNum(word) && hasOneVowel(word) && hasOneConsonant(word);
      }
  
      private static boolean isAlphaNum(String s) {
          for (int i = 0 ; i < s.length() ; i++) {
              if (!Character.isAlphabetic(s.charAt(i)) && !Character.isDigit(s.charAt(i))) {
                  return false;
              }
          }
          return true;
      }
  
      private static boolean hasOneVowel(String s) {
          for (int i = 0 ; i < s.length() ; i++) {
              if (VOWELS.contains(s.charAt(i))) {
                  return true;
              }
          }
          return false;
      }
  
      private static boolean hasOneConsonant(String s) {
          for (int i = 0 ; i < s.length() ; i++) {
              if (Character.isAlphabetic(s.charAt(i)) && !VOWELS.contains(s.charAt(i))) {
                  return true;
              }
          }
          return false;
      }
  }
  