Print the palindromic String of max_len
document . write ( s . substring ( 0 , max_len ) ) ; } function reverse ( input ) { let a = input . split ( ' ' ) ; let l , r = a . length - 1 ; for ( l = 0 ; l < r ; l ++ , r -- ) { let temp = a [ l ] ; a [ l ] = a [ r ] ; a [ r ] = temp ; } return a . join ( " " ) ; }