What to store in the hash table
	Items
		Quickest 
	Pointers
		Pay pointer overhead
		Might waste less ram

Good Hash Functions
	- Distribute data evenly
	- Always compute the same hash for the same input
	- Quick and easy
	- Transpositions result in different answers
	- Not based on non-distribute things
		Area Codes
		First three of SS#
		Ages
Perfect Hash Functions
	- Exist
	- Not used often in the real world.

Collisions
	- Accept them
		useful for existance questions
		Can never delete an item
	- Linear Probing
		Idea:  Move to the next bucket if the current bucket is full
		- Makes delete really hard
			- Can remove an item with dummy entries
			- Might need to do a rebuild
		Exposes any clustering in your hash function.
		Performance:  0.5*(1+(1/(1-a))) if success
		Performance:  0.5*(1+(1/(1-a)))**2) if not found
	- Double Hashing
		Make a second hash function that produces different answers than the first
		Skip hash2(item) each probe to look for an empty space
		hash2(item) and Tablesize must be relatively prime
		Performance:  -ln(1-a)/a if success
		Performance:  1/(1-a)
	- Chaining
		Idea:  Each Bucket is a linked list
		Can add and delete easy
		Requires lots of code.
		Performance:  1+(a/2) if success
		Performance:  a if unsuccessful search
		Performance:  Best if table is dense