That’s it, the 9th post of the series of programming job interview challenge is out and alive. 19 readers provided answers to job interview challenge #8, Pieter G was the first to provide a correct answer:

The fastest way I can come up with is to generate a finite state machine at initialization. The transitions between states would be defined by the records you look for in the pattern and one transition for an unmatched record. When the machine enters the goal state is should send the notification (how to most quickly do that I leave to someone else). When reaching the goal state the machine should not terminate but continue (else we may miss a occurrence).

You can see more details about the solution in those blog entries:

Often we want to display a list of elements and allow the user to sort them in various ways. There are many ways to do it and I wanted to show you how to use a SortDescription Object. What is a SortDescription object you ask? It receives two parameters in its constructor: the first is [...]