Lecture 9

Question 1

In the classes of Algorithms diagram what are NP-HARD

Answer 1

It is a class of problems that can not be solved in the ‘traditional’ way

Typically these problems:
Have a “best known” computational complexity in exponential time, e.g. O(n) = 2^n
They have no direct analytical solution

Question 2

Define Search Problem

Answer 2

For some problems we need to search for a solution from a (usually) very large number of possibilities
Search problems, i.e. searching for the answer in some solution space
The solution spaces for many every day problems can be very, very large, too large to search exhaustively
The search algorithm may not find the optimal solution to the problem, however, it will give a good solution inreasonable time
We often need special search algorithms known as meta-heuristics

Question 3

What is a Heuristic?

Answer 3

A heuristic is a “rule of thumb” or some loose set of guidelines
That may find a solution (but not guaranteed)
E.g. getting out of a maze by keeping your hand against the maze wall

In Artificial Intelligence these are used to improve the performance of methods, in our case, search methods
Expert knowledge