def clustering(self, groups, minheap):
#maxheap is a max heap of edges (one direction only)
unionfind = UnionFind(list(self.graph.keys()))
while unionfind.size() > groups:
#keep merging until number of desired groups reached
curr = minheap.pop()
curr_edge = curr.get_data()
if unionfind.find(curr_edge[0]) == unionfind.find(curr_edge[1]):
#same group
continue
unionfind.union(curr_edge[0], curr_edge[1], True)
while unionfind.find(curr_edge[0]) == unionfind.find(curr_edge[1]):
#pop until different groups to get max distance, because next edge might be within a group
minheap.pop().get_data()
curr_edge = minheap.peek().get_data()
#smallest distance is the edge at the top of max heap since they are in different groups
return unionfind, minheap.peek().get_key()
