Subject 1 is already supported
You can filter languages, just click “ALL SUBMISSION” and then in the top you’ll find two combo boxes titled “Language” and “Result”. For language you can select Java and for result just select AC. You can even click in “Time” to sort the solutions by time (first click for non-decreasing other and second for non-increasing). You can even see the solutions of a single user
yes! specially test cases passed would be great! at least in practice section
Do you write code on the editor provided here? 
Even on SPOJ the editor is not nice (as seen in hackerrank), even there I prefer writing and testing on local machine. Why a better editor?
Easier access to prev submitted solutions? I don’get it. “easier” in what way? We have already pretty straight access. Please explain a bit. 
I like the idea about friend addition. In Google Code Jam and CodeForces I can see ranking of my friends easily, that would be nice 
A device authentication check during login from other device looks like better idea.
The reason, if I’m not wrong, has something with teams (maybe someone can correct or complete than)…
Personally I§d love that, because I have to log in at work and later again at home, cumbersome…
I do not like that idea, you have to realize that there are other competitions and it’s bad if there are two in same time. I love CodeChef, I really do, but if there is TopCoder SRM in same time, I’d participate in TopCoder. And even worst I do not like long contest to be shorter. You have to realize also, that contest duration also determines the difficulty of problems (in longer contest there can be very difficult problem).
@betlista >> When did I say that long contest needs to be shortened? No, it shouldn’t be. 2 weekends is just the ideal time a working guy would want, and also good for us, busy students. Regarding short contests, yes there are SRMs, Codeforces’ ones, but 2 cook-offs can be arranged accordingly with respect to those contests, not a big deal I guess. I just wanted to practice more in the given shorter period of time. Long Contests develop “idea implementations”, Short Contests develop “fast implementations”. Thats what I felt after failure in GCJ 2013. One line: more practice in 2.5 hours period
After getting my ass kicked so badly at a university competition yesterday, I can’t help but to agree with bugkiller… I believe that there’s a point in ones training where the only little thing you need to do to improve again is to put yourself under the knife… And there’s nothing better than a cook-off for that imo
@bugkiller I’m just commenting the post with the most votes, idea about 2 Cook-off’s is here several times also suggesting to make long contest shorter, so I just wrote my two cents. I agree that competing is a lot better than just practicing, but there are other contest pages, you can try CodeForces, UVA, TopCoder (but I recommend just TopCoder).
@betlista >> Oh I thought you might have mistaken the shortening of long contests from some other answer here into my answer. Anyways, and yes in TopCoder SRMs, I thought to try my hands there once I can solve >= 3 problems here (or at Codeforces) easily (within 2 hours). That means after my semester examinations. Human’s inherent tendency to oppose the change, what can I say more 
Yes as @betlista said, when a team contest is going on, then ideally all the team-mates have to be at one place sharing just one machine (to code), that is why multiple logins are not allowed and it throws you out if you do so from another IP address.
@betlista @bugkiller well that’s a valid argument:) but codechef is becoming famous for its superb contests, editorials & active discussions. And how often does codechef really hold a team event? probably once or twice a year? but single events are 2 a month, makes it 24 a year! so which should be given preference? moreover, if there is a team event people will have to register under ONE team name,and then allow only one IP per team at a time, wont that solve it? i really wish i could comment this same thing from my cell as well,instead of having to turn on laptop and waste a lot of time :/
sorry if i dont make sense to some of you. but its just a suggestion coz it wil help a lot of us! waiting for @admin to throw some light on as to why this isnt possible
@sunny_patel >> but multiple logins will be unfair, I tell you how:
In cook-off if person X manages to take a friend with him (say Y) and then they plan in such a manner that X will solve first 3 problems and Y will solve the last 2, say. And they will login from different locations obviously, and they will match the timings so that you can’t doubt on the submissions. Then isn’t it unfair for the contests that way? That way Dzhulgakov might have a tough competition 
for your first query pls go through this…A green mark for solved practice problems - general - CodeChef Discuss
now, it’s available for FF too
Now you can see problems solved by you in contests as well as practice section.
After login, visit easy Problem - CodeChef , go to the category you want and see the problems solved by you in green color with a tick mark. (works for the contests)
While I would appreciate more Cook-Offs per month, if that comes at the cost of quality of the problem set, then I’d rather have one good contest per month than 2 mediocre ones.
@abhijeetpandey Are you sure you are not having any extensions installed? Because, there hasn’t been any official information given out on this from codechef, AFAIK (please correct me if I am wrong).