comefrom: <awangdev>332. Reconstruct Itinerary_1.java
code: private Map<String, List<String>> buildMap(List<List<String>> tickets) {
  
          Map<String, List<String>> map = new HashMap<>();
          for (List<String> ticket : tickets) {
              map.putIfAbsent(ticket.get(0), new LinkedList<>());
              map.get(ticket.get(0)).add(ticket.get(1));
          }
          for (String key : map.keySet()) Collections.sort(map.get(key));
          return map;
      }
masked: private Map < String , List < String >> var_0 ( List < List < String >> var_1 ) {
    Map < String , List < String >> var_2 = new HashMap < > ( ) ;
    for ( List < String > var_3 : var_1 ) {
      var_2 . putIfAbsent ( var_3 . get ( 0 ) , new LinkedList < > ( ) ) ;
      var_2 . get ( var_3 . get ( 0 ) ) . add ( var_3 . get ( 1 ) ) ;
    }
    for ( String var_4 : var_2 . keySet ( ) ) Collections . sort ( var_2 . get ( var_4 ) ) ;
    return var_2 ;
  }
  