I know looping once is more efficient, but I feel like solutions like these break SRP, DRY, and several other principles..
Then again maybe breaking stuff down in functions with high readability are not the point of these kata's...

I've always done string manipulation w/o stringbuilder, and yet I keep seeing solutions more legible than mine that use it. I suppose it's time I read up on stringbuilder, seeing how common it is.

Can be done in linear time.

If you take 100，50 is the priority! 50 can only be found for 100, and 25 should be saved for 50!