Instructions:

You will be given a series of node pairs to union together. For each pair, there is some node should become the immediate parent for some other node. Click first on the node that should become the parent, and click second on the node that should become the child of the node you first clicked on. Use the weighted union rule. If both trees are the same weight, then the one that comes first in alphabetical order should be the root. Click "Already Unioned" if no change should take place for the given node pair.