Kind of a grab bag today.

Topic 1:  Merge Sort
	Stable sort:  Do equal items end up in the same order?
		Merge sort can do that
	
Topic 2:  STL flat sets
	And adapters in general
	Has underlying storage from some other type (usually vector)
	
Topic 3:  Graphs
	STL doesn't have a graph ADT
	Useful to represent a network of any sort
		Users who friend each other
		Nodes in a computer network
		Locations in a RPG
		Topics in a wiki or manual
	So how to do one?
		Adjacency list for each node:
			Good storage efficiency, duplicate for bidirectional graph
		Adjacency matrix:
			Fast, but not very efficient with regard to space
			bidirectional graph:  Symmetric along main diagonal
		Incidence matrix:
			Limits maximum number of edges, or requires resize
			Efficiency depends on connectivity (popular users?)
	Existing pieces from STL:
		Key, with map, set of nodes (or map if edges have values)
		Running time for each operation on Wikipedia
	How about calculating a minimum spanning tree?
		Dijkstra's Algorithm
	Graph isomorphism:	
		It's in a special complexity class
		There's actually been some progress since I last looked at this problem