Declaration and initialization of counter array
str = ( str . slice ( 0 , Math . floor ( l / 2 ) ) . sort ( ) ) . concat ( str . slice ( Math . floor ( l / 2 ) , l ) . sort ( ) ) ; for ( let i = 0 ; i < Math . floor ( l / 2 ) ; i ++ ) if ( str [ i ] != str [ Math . floor ( l / 2 ) + i ] ) return true ; return false ; }