text: Array to store required prefix count of 1 s from right to left for boolean array
code: int [ , ] p_arr = new int [ n , n ] ; for ( int i = 0 ; i < n ; i ++ ) for ( int j = 0 ; j < n ; j ++ ) p_arr [ i , j ] = 0 ; findPrefixCount ( p_arr , set_bit ) ;