Hello everyone!
Codeforces Round #235 (Div. 2) will take place on March 10th at 19:30 MSK.
This is my first Codeforces round and I hope not the last one.
I'd like to thank Gerald Agapov (Gerald), Roman Rubanenko (Rubanenko), Sergey Oryshych (Oryshych) for helping me to prepare round, and Mariya Belova for translation of all problem statements into English.
Scoring: 500-1000-1500-2000-2500
GL & HF!
Top five:
Congratulations of participant hoanglmdiv2, who solved the problem E.
Unfortunately, my fault, in the round hit the problem that was previously used on another competition. Since it does not comply Codeforces, problem E will be deleted.
Hope your last (Div. 2) only contest!
Only your contest (Hope. 2) last div!
I think, there's 2 ways to deal with current situation with Div.2 Only contests (I mean, their low popularity) — either get rid of them at all or create Div. 3!
-of-j
Za chto ti ego tak nazivaesh?
prost)))
Good luck with you first round.
Daylight saving time begins... contest is one hour later than usual in my area : )
I think your contest will be very interesting!
It's impossible to register out-of-competition.
Me also facing same problem.
Same problem.
The same.
The same!!, sadness))
you are div2 how to be the same ?
I am sorry, forgot to check feature. Now it works.
div2 only.....what a pity..
Bugs or new rules ? I can't take part in it out-of-competition.
If it be a new rule, tonight top 100 will be new users ! God help us ...
It's working now. And I think most of Div1 coders will take part in it out-of-competition.
Я первое место забил уже
The time is too late.
if ur really dedicated, then u will participate no matter what the time and place!
hope out from newbie.
:D
Good Luck Manurung :)
hope , you will arrange more div1 cntests B|
The contest hasn't start yet, but server is already unavailable :)
For problem C, if multiple such sequences are possible, can we print any of them?
Yes, but i advice you to use such a function as "Ask a question" :)
My solution was hacked, but didn't change color to red in the table. Did anyone have the same problem?
did u refresh ur room after it was hacked?
What's pretest #4 for E?
I spend lots of time to pass that test and haven't make it during the contest.
E is a very nice problem by the way.
2 2 8
10 15
5 6 1000
can't be this one.
My output is same as cgy4ever's for this test.
ignore Bredor, he's a troll (as u can see from his comments)!
nice match vs West Brom
what is the idea of problem D?
I thought of a DP : (2^18)x(18)x(100) but obviously will fail x/
Why fail? Actually it works well. 5978987 — AC in 1.637.
Getting TLE on 38 :(, Submission link
I managed to update your solution a little bit, so it passed TL: 5990582 and then 5990630.
i didnt understand, why is some people need divide it by the factorial of sums each number, and while others isnt
my old code got tle too http://codeforces.net/contest/401/submission/6011014
then i tried just need use 1 array, separating value of old array and new array with the numbers of bits that's on
Depends on whether your DP takes care of identical digits in the same level or not ..
for test case 2, n = 223, it has 6 possible permutations, however it has 3 distinct numbers only.
Therefore, if you make sure not to take duplicate numbers into consideration, you won't need to divide by sum of factorials. Otherwise you do.
yes, that's what i thought too, but i failed to find in their code how is they managed to do it
for example, like the code commented below, http://codeforces.net/contest/401/submission/5984009
i just didnt see the part which is take care of leading zero, or duplicate numbers
maybe i need much more training reading others code
I haven't understood the whole code, but he handles that, by the fact that he only loops from (0-9) each time he makes the update on his current state of DP. And as for the Leading zero, I believe it's handled somehow using the bool lz ..
Dammit :\
5990127
Did not expect a ~10^9 solution to pass. Wasted 15 mins to find optimisations to bring it under ~10^8
You may use CUSTOM INVOCATION to test execution time of your solution, if you are not sure. Just have to choose realy "worst case". For example, my friend failed this problem today, because he tested on 112233445566778899 100 and it worked well — but m=100 isn't worst case for this problem, 'cause with it most states can't be reached — some large prime like 97 will give much harder case.
dp[i0][i1][i2][i3][i4][i5][i6][i7][i8][i9][r] = the number of ways to use i[j] j' to form a number without leading zero and mod m = r
dp with 11 dimensions? I like it.
Also, look at 5988053... It's realy nice one.
I tried your solution but recursively the problem i faced is how i can dynamically create a global array (array with variable like your local one ). do you have a solution for that
check my submission [submission:http://codeforces.net/contest/401/submission/5984009]
using g++ you can do this:
dp[mask][k] = amount of close numbers to n such that they are compound by digits of n that appears in mask, and are congruent k with m. Complexity is 2 ^ 18 * 10 * 100. 5987971
When will ratings be updated ???
A moment before you will get -100
HAHAHA really funny
is it just me, or had this blog post suddenly disappeared for about 5-10 minutes? i didn't see it in the home page nor in the recent actions tab (both simple and detailed)!
i didn't see it as well .
In EG0R's blog either.
Round Statistics
P.S. Hacks stats will be published after hacks page become available.
I think people in china can't connect to codeforces.com without goagent anymore after this contest......
Why?
Because the 1st place of this contest 's name is our president......
Dude, are u serious..
Now, all of his submissions are skipped...
I think it's really very funny
i think the actual reason for that is because he had registered on CF just recently, and was found to be a Div-1 participant who created a new account just to participate in today's contest!
I think it's very funny too.......
GoodByeAhu
Registered 7 hours ago
XiJinping
Registered 12 hours ago
OrzSKYDEC
Registered 4 days ago
Isn't it strange?
All of them are unrated and registered a few days ago.
i soved one problem successfully in div 2 round 235, still my rating is unchanged(stuck at 1410). Can u please explain why?
i guess the rating hasn't been updated...
As always...
Why most of the contestants in top 100 are mostly unrated? Are they div1 candidates who just register to participate with new identity?
@Egor, @Author I don't understand, why questions B and C were so easy, also they needed implementation only I think, C was easier than B.
Because this is his the first contest
Our great president XiJinping has taken part in this round and did a good job (rank1 in unofficial). But now I cannot find him:-)
His submissions are ignored :)
President Xi must be very confused: why ignore me! Though I'm a president, I have the right to fight for codeforces!
Problem C (div 2) should contain algorithmic problems. Problems A and B are sufficient to test implementation, simulation or simple maths.
Can you please explain me the rating system used in code forces. I participated in div2 round:235 and solved first problem successfully and submitted a wrong answer for second problem . My rating before the contest was 1410 and now it has been decreased to 1318. Can you please explain this because I think my rating should have increased!! Thanks in advance.
the new rating depends on your previous rating and your current contest rank (and not on number of problems solved)
In Russia, man who solved 1 problem in div2 is called RAK
what is RAK?
it's a person with low skills, but Bredor's not adequate enough, so don't pay attention
TOP-4 (2, 3, 4, 5 places) were unrated and registred some hours ago... :(
Problem E is from a past USACO gold contest. Problem statement
WOW! Totally the same!
for problem 235A ,my code is showing different answer on ideone and different answer on compiler of codeforce...why is it so?? link for my code http://codeforces.net/contest/401/submission/6013925