I'm not quite sure how to read your comment. Are you expressing surprise at that, or suggesting it as a semi-obvious explanation? I would say that once you've

I'm not quite sure how to read your comment. Are you expressing surprise at that, or suggesting it as a semi-obvious explanation? I would say that once you've chosen the correct algorithm to implement and understood it deeply, writing algorithmic code often isn't so difficult. In contrast, interfacing with existing systems can be arbitrarily complicated, if you're handed something with arbitrarily bad design.