If you don't know what is the difference between O(n) and O(n^2) and how to make a data structure that allows you to keep the data sorted in particular way, you can get by using ready-made things up to some point. When that point comes, your "where to ask" would be "take a course in algorithms design and data structures and/or read a fat and quite dense book". Which is a completely OK way to advance your knowledge - except that some employers may prefer to hire people that already did that, and not wait with the task at hand until they do.