If count of occurrence of characters is odd
if ( hash [ i ] % 2 ) { if ( ! f ) { res1 . push ( String . fromCharCode ( i ) ) ; f = true ; } else { res3 . push ( String . fromCharCode ( i ) ) ; } } } return ( res1 . join ( ' ' ) + res2 . join ( ' ' ) + res3 . join ( ' ' ) ) ; }