int knapsackRec(int[] w, int[] v, int n, int W) {
if (n <= 0) {
return 0;
} else if (w[n - 1] > W) {
return knapsackRec(w, v, n - 1, W);
} else {
return Math.max(knapsackRec(w, v, n - 1, W), v[n - 1]
+ knapsackRec(w, v, n - 1, W - w[n - 1]));
}
}