In this problem the thing is if sum of all number is even ,then array can be even. if sum of all number is odd , then the answer is NO.

My java solution is here;

public class Solution {

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int N = in.nextInt();
    int B[] = new int[N];
    int sum = 0;
    for(int B_i=0; B_i < N; B_i++){
        B[B_i] = in.nextInt();
        sum+=B[B_i];
    }

    int count = 0;
    if(sum % 2 == 1){
        System.out.println("NO");
    }
    else{
        for(int i = 0; i<N; i++){
            if(B[i] % 2 != 0){
                B[i] = B[i] + 1;
                B[i+1] = B[i+1] + 1;
                count+=2;
            }



        }
        System.out.println(count);
    }
}

}