Here is a program written in C that demonstrates 2 median/selection
computation techniques:
ACM Algorithm 727 (implementation by Sherif Hashem)
QuickSelect (implemented by me).
Since it is written in C, it would be useful to PostgreSQL project
without any fanfare.
ftp://cap.connx.com/pub/chess-engines/new-approach/727.c
The ACM agorithm 727 is an approximation.
The QuickSelect result is exact.
