Collisions

While there are cases in which perfect hash functions can be constructed, this is unusual.

Usually, we will have two distinct objects and such that (their hash values are the same).

We call this a collision, and all the action in hashing is in dealing with them.

• Example: h(k) is the sum of the letter values of the first and last letter of k's last name.
• Two collisions: Nate Rogers and Jon Seeber, David Raymond and Jeff Dillinger.