private static int solve(String s) {
        String[] a = s.split("\n");
        int sum = 0;
        for (int i = 0; i < a.length; i++) {
            String[] aa = a[i].split("\t");
            int max = Integer.MIN_VALUE;
            int min = Integer.MAX_VALUE;
            if (aa.length == 0)
                continue;
            for (int j = 0; j < aa.length; j++) {
                int current = Integer.parseInt(aa[j]);
                min = Math.min(min, current);
                max = Math.max(max, current);
            }
            sum += max - min;
        }
        return sum;
    }
Why Did you create this class? what does it do?
src/adventofcode/CheckSUm_2.java