The 0 is a acceptable answer. We need minimum the number of North poles.

Just try it. There are only +/- operations so that the server can do more operations in a second.

The O(n^2) solution is accepted. Because the server can do 10 million operations in a second

It's seem like you used 2 pointers.

Can you show a link to your solution, thanks

Yes, I think so.

I'm just taking rank1 as an example. I mean maybe the strategy should be changed a little.

I think there are some problems with that. According to the prediction results of CF preidcitor, the div4 rank1 will increase 341 score after this round. So, his new rank will be 1733 (1392+341). I think it unbelievable. Maybe his new rank is too high.

Althogh i solved all problems, but CF predictor tell me that my rating will go down. X:) (just for fun)

This is wrong answer. Because it's not possible for a north magnet to occupy black cell after some sequence of operations from the initial placement.

What's your meaning, The 3*3 grid is all colored white?

Because North pole can't occupy white cell, and North pole can reach the cell which be occupied by South pole if they are in same Column or Row.

I'm sorry to say that i think you will get TLE again on rejuding stage. And it almost impossible rejudge the contest again!

You should read contest rules carefully! The rules are as flows!

The registration confirms that you:

• have read the contest rules by the links http://codeforces.me/blog/entry/456 and http://codeforces.me/blog/entry/4088
• will not violate the rules described on http://codeforces.me/blog/entry/456 and/or http://codeforces.me/blog/entry/4088
• will not communicate with other participants, share ideas of solutions and hacks
• will not use third-party code, except stated in http://codeforces.me/blog/entry/8790
• will not attempt to deliberately destabilize the testing process and try to hack the contest system in any form
• will not use multiple accounts and will take part in the contest using your personal and the single account.

There are so many submissions on system test stage, the server have lower performance than normal case. And you code runs 1996ms, it's too close 2000Ms. So your code get TLE on systen test stage.

The answer is as follows

2
4 1 2 3 6
2 4 5

Maybe, It's like this

6 6
1 2 3 4 5 6
4 3 2 2 1 1

I think you are right. The statement of B make me confused!

I think so. This round will end at 1.05 am. It's a little late for me!

Maybe

I think you misunderstand the problem E statement. this testcase will shou you
~~~~~ 1 8 2 1 1 2 2 2 1 1 ~~~~~ The correct answer is 7

try this test case 1 5 1 1 1 1 1 you will get wrong answer

What's wrong?

As I said before, it not need sort it. For this case 5 3 1 1 5 if you sort it ,you will get wrong answer.

I find it. Because it not need be sorted!

In Div2 problem C, I make the l array non-ascending. And, if sum(l1+...+lm)<n print -1, else for 1 to n, if
i+l[now]-1<=n, then ans[now]=i, sum-= l[now], now++ ,else print -1. But it get wrong answer pretest4! Can someone tell me why, please? Here is my code 75414479

I also have tried to log in m1 mirror site, but it not work. But thanks codeforce for providing a practice environment to me.

what the fuck! I can't access the codeforce after submitting A until div3 over! It always show 403 forbidden or log out my account. No other meaning, I'm just bringing up what happened to me.

so sad, this sentence "Then output k distinct integers (1≤pi≤n), indexes of the chosen elements" in div2 A, Let me misunderstanding, i think it's k distinct integers a[i], not the index of a[i].

I have no idea for div2 D!!!

thanks,but FFT also get ac

So bad,My fft don't solve div2 C!!! I think it maybe overflow