Stackoverflow is a great site for finding answers to coding questions (and for asking new ones if you can’t find what you seek).
But!
There is a whole network of Stackexchange sites, some of which concern puzzles (amongst other delightfully nerdy subjects).
For today’s warmup, you should visit two of them: Puzzling and Codegolf.
Try at least the following problems (without looking at the answers already submitted!):