private static void printDuplicates ( int [ ] arr , int n ) {
  Map < Integer , Integer > map = new HashMap < > ( ) ;
  int count = 0 ;
  boolean dup = false ;
  for ( int i = 0 ;
  i < n ;
  i ++ ) {
    if ( map . containsKey ( arr [ i ] ) ) {
      count = map . get ( arr [ i ] ) ;
      map . put ( arr [ i ] , count + 1 ) ;
    }
    else {
      map . put ( arr [ i ] , 1 ) ;
    }
  }
  for ( Entry < Integer , Integer > entry : map . entrySet ( ) ) {
    if ( entry . getValue ( ) > 1 ) {
      System . out . print ( entry . getKey ( ) + " " ) ;
      dup = true ;
    }
  }
  if ( ! dup ) {
    System . out . println ( "-1" ) ;
  }
}

private static void printDuplicates ( int [ ] arr , int n ) { Map < Integer , Integer > map = new HashMap < > ( ) ; int count = 0 ; boolean dup = false ; for ( int i = 0 ; i < n ; i ++ ) { if ( map . containsKey ( arr [ i ] ) ) { count = map . get ( arr [ i ] ) ; map . put ( arr [ i ] , count + 1 ) ; } else { map . put ( arr [ i ] , 1 ) ; } } for ( Entry < Integer , Integer > entry : map . entrySet ( ) ) { if ( entry . getValue ( ) > 1 ) { System . out . print ( entry . getKey ( ) + " ▁ " ) ; dup = true ; } } if ( ! dup ) { System . out . println ( " - 1" ) ; } }
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