comefrom: <awangdev>720. Longest Word in Dictionary_1.java
code: public String longestWord(String[] words) {
          if (words == null || words.length == 0) {
              return null;
          }
          String result = "";
          Arrays.sort(words);
          
          Set<String> set = new HashSet<>();
          set.add(result);
          
          for (String word : words) {
              if (set.contains(word.substring(0, word.length() - 1))) {
                  if (word.length() > result.length()) {
                      result = word;    
                  }
                  set.add(word);
              }
          }
          
          return result;
      }
masked: public String var_0 ( String [ ] var_2 ) {
    if ( var_2 == null || var_2 . length == 0 ) {
      return null ;
    }
    String var_7 = "" ;
    Arrays . sort ( var_2 ) ;
    Set < String > var_12 = new HashSet < > ( ) ;
    var_12 . add ( var_7 ) ;
    for ( String var_14 : var_2 ) {
      if ( var_12 . contains ( var_14 . substring ( 0 , var_14 . length ( ) - 1 ) ) ) {
        if ( var_14 . length ( ) > var_7 . length ( ) ) {
          var_7 = var_14 ;
        }
        var_12 . add ( var_14 ) ;
      }
    }
    return var_7 ;
  }
  