static int knapsackRecursive(final int[] v, final int[] w, final int c, final int beg) {
        if (c == 0 || beg >= v.length) {
            return 0;
        }
        int max = Integer.MIN_VALUE;
        for (int i = beg; i < v.length; ++i) {
            if (w[i] <= c) {
                int ans = v[i] + knapsackRecursive(v, w, c - w[i], (i + 1));
                max = Math.max(max, ans);
            }
        }
        return max;
    }

    static int knapsackRecursiveCaller(final int[] v, final int[] w, final int c) {
        return knapsackRecursive(v, w, c, 0);
    }