But since the checklist gets updated from time to time, I found it hard to migrate from the previous checklist to new checklist. So, I made the following web app for the same purpose! Now you don't need to worry about migrating, I can just add the problems to database and it'll update automatically!
Link: OI Checklist
Please find the features and changes to the main checklist bellow:
Features and Changes
First of all, now the checklist contains direct link to each problem, while the main checklist had link to some parent of the link. And clicking on a contest name will lead to the official "Task" page of that contest, which generally contains judge data, editorial etc. In case this is not available, a related page is linked.
Each category has a progress bar above it, so you can easily see how much you've solved.
Many of us want to keep our checklist secret. Don't worry, you're checklist is always secret. However, you can share a static link your checklist.
You can see statistics of a problem by hovering over the cell. Currently the statistics include the number of perfect scorer in official contest and the statistics that was given in IOI 2018, that is, the percentage of points that was scored at that problem during contest. So you can get used to this kind of stats.
Toggling state of a problem is easy, just click on the cell. It will change state from unsolved to solving to solved.
Some problems that are added in oj.uz but not available for public is marked in red. Since oj.uz shows that output only tasks is under testing, you can keep track of them. And problems that are not available or POI problems that doesn't have translation yes are marked in black.
Hope you'll like it. What other features would you like to see?
(This is not well tested yet. If you find any bugs please let me know)
UPDATE 1: As Benq suggested, now you can turn the state of a problem to an additional color: Blue. Meaning you already know the solution to the problem but don't intend to implement it for now. But the count of such problems will be added to solved problems for the status bars. The blue color is barely different from the green one as there is small difference between knowing solution and implementing it.
UPDATE 2: All USACO problems from session 2012-2013 to 2018-2019 are now added. Now the list contains 733 problems.
UPDATE 3: Some CEOI Problems were not available in oj.uz, but they are available in cses.fi, so updated all CEOI problems' links from cses.fi. Now BOI problems have direct links to the contest in cses.fi (previously https://cses.fi/boi/list/ was linked with each of the BOI problems), same goes for CEOI problems.
UPDATE 4: Sorry :( The app has exceeded the free row limit in heroku. So, I've taken it down in Maintenance Mode. I'll keep the post updated if I manage to host it somewhere else. :(
UPDATE 5: Migrated from Heroku to PythonAnywhere. Now the app is running on https://oichecklist.pythonanywhere.com. All data from the previous app was imported into this. Yet if you find some inconsistency in your checklist please inform me. You may want to search your browser history and delete all entries of oichecklist.herokuapp.com. Happy practicing. :)