public static int atMostSum(List<Integer> a,
                                int k)
    {
        int sum = 0;
        int cnt = 0, maxcnt = 0;

        for (int i = 0; i < a.size(); i++) {

            // If adding current element doesn't
            // cross limit add it to current window
            if ((sum + a.get(i)) <= k) {
                sum += a.get(i);
                cnt++;
            }

            // Else, remove first element of current
            // window.
            else if(sum!=0)
            {
                sum = sum - a.get(i - cnt) + a.get(i);
            }

            // keep track of max length.
            maxcnt = Math.max(cnt, maxcnt);
        }
        return maxcnt;
    }