Only Even !

A Subarray is an array taken from a original array between any two indices L and R where $L<=R<=N$ and N is the Size of the given array.

Now you are given an array having N elements and your task is to find the count of all the subarrays whose product of its elements is Even.

Example:

Input: n=3, arr={2,3,4}
Output: 5

Approach

Java

public class OnlyEven {
    public static void main(String args[]) throws Exception {
        int n = 3;
        int cntod = 0;
        long res = n * (n + 1) / 2;
        int arr[] = { 2, 3, 4 };
        for (int i = 0; i < n; i++) {
            if ((arr[i] & 1) == 1) {
                cntod++;
                while (++i < n) {
                    if ((arr[i] & 1) == 0)
                        break;
                    cntod++;
                }
                if (cntod == 1)
                    res--;
                else
                    res -= (cntod * (cntod + 1)) / 2;
                cntod = 0;
            }
        }

        System.out.println(res);

    }
}