If you want to patent an algorithm, you have to frame it as a computer system executing it.
Then it's mechanical; phew. The default euphemism for algorithm is "system and method."
Try a patent search for that phrase and see how many results you get
Yup. Guilty as charged. These are issued patents that I was involved in filing for over 5 years ago and pretty much forgot about until a couple of months ago. I guess they finally made it through the labyrinth of the Patent Office and were actually granted. Look, ma, I'm an inventor !
[Just to be clear -- I don't think that the "systems and methods" described in these patents are particularly "non-obvious", but, hey, I was young and needed the money.]