CodeAbbey

At last. Exercises on Programmable Logic - in Verilog language. I thank colleagues who helped me to start this new page in our website's history. https://lnkd.in/dhJSNvdZ

New task - checkmate with Rook! As we study general algorithms, at some moment we usually come to implementing "minimax" for game like tic-tac-toe, checkers or chess. Interesting, but while enumerating possible moves in chess position is a comparatively big task, it is not quite difficult for student or even school pupil - and hence writing code for "solve mate in two (three, four)" - is not particularly difficult also (just build a list of moves and try them recursively). But when it comes to situation of endgames, this straightforward approach often fails. For example, single rook can make 10+ moves from most positions and to reach checkmate we may need 10+ double-turns. This makes tree of search excessive, with no simple points gain/loss until the end. How should we deal then? It is probably not very difficult either but need some thinking - feel free to try in the new task (which is also a task of a new kind - interactive, but running in sandbox).

Some features wait for years without obvious reason :) This one for example. When we submit the answer, originally website changed page to /index/task_attempt - and here the user have seen results. As results are more often wrong than right, one needs then click "Try Again" and the task page is reloaded, could be scrolled down again etc. This flow was simply copied from ProjectEuler (which was inspiration for CodeAbbey). And it is not uncommon. Even CodeForces will change page on submission! But I long felt it is not convenient and may look archaic even for so archaic design like ours. So from now wrong results are instead reported in modal dialog (with the same fields - your answer, expected answer and test data). On success however the user is redirected to the page looking exactly the same as previously (but actually different). This allowed, besides improved user experience, to split the logic in Attempt.php controller - previously it was responsible both for checking the task result - and for loading various auxiliary data in the case of success.

CodeAbbey is going opensource by and by. Here is a video of deploying it to free web-hosting - so that everyone can setup similar site in 30 minutes. https://lnkd.in/dXK8YGhG