// Read all the children
        idx += doParseTrieToBuilder(stack, encoded, idx, builder);

        if (encoded.charAt(idx) == '?' || encoded.charAt(idx) == ',') {
          // An extra '?' or ',' after a child node indicates the end of all children of this node.
          idx++;
          break;
        }
      }
    }

    stack.pop();
    return idx - start;
  }