depth method

int depth()

Implementation

int depth() {
  int maxSubDepth = 0;
  for (int i = 0; i < 4; i++) {
    if (subnode[i] != null) {
      int sqd = subnode[i]!.depth();
      if (sqd > maxSubDepth) maxSubDepth = sqd;
    }
  }
  return maxSubDepth + 1;
}