two disjoint sets are given (1) Union: If Si and Sj are two disjoint sets, then their union is Si Sj = {x | x is in Si or Sj}. (2) Find(i): Given an element i, find the set containing i. Make the root of the tree with lower depth be a child of the root of the tree with higher depth. (If two trees have the same depth, choose arbitrarily.) Show that UNION can be done big-Oh(1) time and FIND can be done in O(log n) time.