Revision:Algorithms

TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Mathematics > Algorithms

An algorithm is defined as a finite sequence of unambiguous instructions for solving a problem.

• Every algorithm requires an input
• The output depends only on the input
• The algorithm must terminate in a finite time for all inputs (it doesn't get stuck in a loop)

Order

The order of an algorithm is a measure of the approximate run time for an algorithm, depending on the size of the problem. For large problems we only need to consider the dominant term to get an approximate run time.

The efficiency of an algorithm is a measure of how well an algorithm copes with an increase in the size, n, of a problem. The efficiency decreases as run time increases.

Order	Run time proportional to
Linear
Quadratic
Cubic
Exponential	or

Example

A computer takes 2 seconds to solve a problem of size 30. Estimate the times taken to solve a problem of size 300 if the algorithm used has

• an order n

• an order n²

• an order n³

• an order 2ⁿ

Therefore, using n = 300

Also See

See the other D1 notes:

1. Algorithms
2. Sorting algorithms
3. Packing algorithms
4. Graphs and networks
5. Minimum connector problems
6. The shortest path
7. Route inspection
8. The travelling salesman problem
9. Linear programming
10. The simplex algorithm

Comments