Lowest n Numbers in an Array

Question

How can I assemble a set of the lowest or greatest numbers in an array? For instance, if I wanted to find the lowest 10 numbers in an array of size 1000.

I'm working in C but I don't need a language specific answer. I'm just trying to figure out a way to deal with this sort of task because it's been coming up a lot lately.

Answer 1

QuickSelect algorithm allows to separate predefined number of the lowest and greatest numbers (without full sorting). It uses partition procedure like Quicksort algo, but stops when pivot finds needed position.