If the way the CCC problems are displayed on a users page could be fixed that would be great. Currently they seem a bit messy/unsorted when you solve problems from both the junior and senior contest. Here's an example. 
[url]http://puu.sh/g4D7R/6f03337d05.png[/url]

This is generally okay but may be wonky in select cases. I'll look into it.

It would be helpful a button to hide the "points" column, so that one can practice with past contests without having prior knowledge about the difficulty of each problem.

Make it easy to sort by column, without having to perform a search. I want to start with easy problems just by clicking the Points column. Click again to sort in ASC/DESC. I also want to sort problems on AC rate.

You can now sort by clicking column headers for "Code", "Points", and "Users". Clicking again will sort in reverse.
Determining the Users Solved and AC Rate right now is really inefficient because they're calculated on the fly.
If Brian ever considers moving those values to the database, I will be happy to implement it.

I like the sorting and "Hide Solved" features on the Problems page but would be super awesome if my choices were sticky so I didn't have to sort and hide each time I come to the page. :)

That makes sense. On my todo.

Edit: Done. A few other improvements to the problems page have been made as well.

Thank you! It looks and works great!!

It would be useful if we can search for, say, only 15 point problems. It would be really useful for training.

make AC green in execution results just cause

Having a filter function on the all submissions and best solutions pages. For example a filter that only shows the submission in your default language

maybe sort problems by AC rate %

It would be nice if there was some indication on another users page to show if you have solved the problem or not. Thanks.

Not sure if this can be considered a user interface aspect, but I found many time browsing the best submissions and willing to comment/ask the user for info or suggestions and the like.

I think that (possibily coupled with a notification system once a post of yours gets commented) would be a HUGE improvement overall: I myself see the best submissions page as the prize I get for solving a problem, so being able to interact with other skilled coders would be icing on the cake.

Just suggesting and still very grateful to you all, staff members, and to Brian Bi for linking this site to me back on Quora :)

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[*]In the middle of grading, display which (or at least how many) test cases are remaining on the submission status page so the user has an idea.
[*][s]Some way to efficiently display threads in the main comment feed. Right now, all it takes is a small series of replies to fill it up completely.[/s] Done.
[*][s]Display full announcements on the front page, not just their titles and a link to this page.[/s] Done.
[*][s]In long threads, display only recent replies by default, with the ability to expand and view all replies. Long threads can really get ugly (like this one).[/s] Done.
[*]In conjunction with hiding comments from the feed if they're from different contests (or main judge), have an easy way for the contest setter to post announcements/updates to the main page of the contest. Even support pushing out an alert() box to inform everybody of an update during a contest (like in Codeforces).
[*]Less of a UI chance and more of a general suggestion, but we probably need to be able to control how much output preview is shown for individual problems (especially in contests, where problem-setters might want to disable previewing altogether).
[*]When more development is done on problem-setter support, a nice native Javascript UI to edit problem statements. (I can look into this.)
[*][s]Better search. Searching "The Primes" shouldn't return over 1000 problems in default order simply because MySQL full text search found "the" in all statements. (I can look into this too.)[/s]  Done.
[*]Eventually, we might get too many users so that the rank list has to be split into multiple pages. If we do this, I think we should consider (or at least have an option to enable) showing all users, not just active ones. The prerequisite, of course, is to improve management of spam accounts.
[*]Since "Default" problem sorting is now based on contest problem keys for more flexible problem codes and better grouping, we can support pages that list problems from a particular contest (e.g. an extra line under time/memory limits on ccc14 problem statements saying "From: CCC 2014" with CCC 2014 linking to a page listing problems from CCC 2014). We can even go as far as having back and forward arrows on problem pages to navigate the contest problems. This can be implemented either by examining the categories or contest problem keys of problems.
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