arguments and that respectively represent the sets and (that isa and qwe perform this operation by making one of the trees subtree of the other (figure )which can be done in ( time by setting the set reference of the root of one tree to point to the root of the other tree operation find for position is performed by walking up to the root of the tree containing the position (figure )which takes (ntime in the worst case note that this representation of tree is specialized data structure used to implement partitionand is not meant to be realization of the tree abstract data type (section indeedthe representation has only "upwardlinksand does not provide way to access the children of given node figure tree-based implementation of partition(aoperation union( , )(boperation find( )where denotes the position object for element