Hello everyone, have you ever faced a situation where you get a non-AC verdict on a certain testcase, but you are unable to debug your solution because you can't analyze (or view) that large testcase? or you are pretty close to the the solution, but don't want to look at the editorial yet, and wished you had more (small) testcases to brainstorm on paper? or a situation in which you feel you could've debugged your solution better if you could just run them on the hack-testcases (which are usually placed at the end of the test-set)?
cfdebug.org cfstress.com to help you in the above situations. It's a tool through which you can see all the small/corner testcases for any problem on Codeforces. By defult, it's sorted by input size (so that it's easier to dry run on paper), but if you get WA on, say TC19, you can filter it to remove all smaller testcases with index less than 19. This way, you'll have access to the next smallest testcase for you to debug.(Temporarily removed). You can also copy the input/output to test the program seamlessly on your local environment.
It works best for older problems, where we did not have multiple testcases per input, and the individual inputs were carefully placed later in the test-set.
The workflow is same as before, enter the contest_id (which you can find by looking at the URL of a problem) and problem_index, and click on Stress Test. On the next screen, click on View Hacks to view all the smaller testcases in the test set.
Let me know your feedback/suggestions/feature-requests in the comments.