Find number of subarrays with even sum | C ++ 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
#include <iostream> NEW_LINE using namespace std ; 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 ) ; } int main ( ) { int arr [ ] = { 1 , 2 , 2 , 3 , 4 , 1 } ; int n = sizeof ( arr ) / sizeof ( arr [ 0 ] ) ; cout << " The ▁ Number ▁ of ▁ Subarrays ▁ with ▁ even " " ▁ sum ▁ is ▁ " << countEvenSum ( arr , n ) ; return ( 0 ) ; }