Sum of squares of all Subsets of given Array | Java implementation of the approach ; Function to return ( 2 ^ P % mod ) ; Function to return the sum of squares of subsets ; Sqauaring the elements and adding it to ans ; Driver code
class GFG { static final int mod = ( int ) ( 1e9 + 7 ) ; static long power ( int p ) { long res = 1 ; for ( int i = 1 ; i <= p ; ++ i ) { res *= 2 ; res %= mod ; } return res % mod ; } static long subset_square_sum ( int A [ ] ) { int n = A . length ; long ans = 0 ; for ( int i : A ) { ans += ( 1 * i * i ) % mod ; ans %= mod ; } return ( 1 * ans * power ( n - 1 ) ) % mod ; } public static void main ( String [ ] args ) { int A [ ] = { 3 , 7 } ; System . out . println ( subset_square_sum ( A ) ) ; } }