private void combinations(int start, int n, int k) {
        if (k == size) {
          processCombination();
          return;
        }

        for (int i = start; i <= n; i++) {
          comb[k] = i;
          combinations(i + 1, n, k + 1);
        }
      }
private void combinations(int start, int n, int k)