Delphi High Performance. - Second Edition

3

Fixing the Algorithm

In the previous chapter, we explored the concept of performance and looked at different scenarios where we would like to make a program faster. The previous chapter was largely theoretical, but now is the time to look at it in a more practical way.

There are two main approaches to speeding up a program, as follows:

• Replace the algorithm with a better one
• Fine-tune the code so that it runs faster

I spent lots of time in the previous chapter discussing time complexity simply to make it clear that a difference between two algorithms can result in an impressive speed-up. It can be much more than a simple constant factor (such as a 10-times speed-up). If we go from an algorithm with bad time complexity (say, O(n2)) to an ...