text: Stores the frequency of each character in strings of A [ ]
code: var A_fre = Array . from ( Array ( n1 ) , ( ) => Array ( 26 ) ) ; for ( var i = 0 ; i < n1 ; i ++ ) { for ( var j = 0 ; j < 26 ; j ++ ) A_fre [ i ] [ j ] = 0 ; }