Find number of subarrays with even sum | Java program to count number of sub - arrays whose sum is even using brute force Time Complexity - O ( N ^ 2 ) Space Complexity - O ( 1 ) ; Find sum of all subarrays and increment result if sum is even ; Driver code
import java . io . * ; class GFG { static int countEvenSum ( int arr [ ] , int n ) { int result = 0 ; for ( int i = 0 ; i <= n - 1 ; i ++ ) { int sum = 0 ; for ( int j = i ; j <= n - 1 ; j ++ ) { sum = sum + arr [ j ] ; if ( sum % 2 == 0 ) result ++ ; } } return ( result ) ; } public static void main ( String [ ] args ) { int arr [ ] = { 1 , 2 , 2 , 3 , 4 , 1 } ; int n = arr . length ; System . out . print ( " The ▁ Number ▁ of ▁ Subarrays " + " ▁ with ▁ even ▁ sum ▁ is ▁ " ) ; System . out . println ( countEvenSum ( arr , n ) ) ; } }