code: public int getSupport(int[] itemset) {
          if (root.children != null) {
              return getSupport(itemset, itemset.length - 1, root);
          } else {
              return 0;
          }
      }
docs: Returns the support value for the given item set.
  @param itemset the given item set. The items in the set has to be in the
  descending order according to their frequency.
  @return the support value (0 if not found)