code: KamNode[] concat(KamNode[] nodes1, KamNode[] nodes2) {
          KamNode[] ret = new KamNode[nodes1.length + nodes2.length];
          arraycopy(nodes1, 0, ret, 0, nodes1.length);
          arraycopy(nodes2, 0, ret, nodes1.length, nodes2.length);
          return ret;
      }
docs: Concatenate arrays {@code nodes1} and {@code nodes2}.
  
  @param nodes1 KAM nodes
  @param nodes2 KAM nodes
  @return KamNode[]