static int countSubarray(int arr[],
                             int n, int k)
    {
        int start = 0, end = 0;
        int count = 0, sum = arr[0];

        while (start < n && end < n) {

            if (sum < k) {
                end++;

                if (end >= start)
                    count += end - start;

                if (end < n)
                    sum += arr[end];
            }

            else {
                sum -= arr[start];
                start++;
            }
        }

        return count;
    }