### dreamoon_love_AA's blog

By dreamoon_love_AA, history, 5 years ago,

Sorry for my bad English >__<

There is a small contest called "Weekly Training Farm #14" hosted in one hour latter.

Weekly Training Farm Contest Series are hosted in Codeforces group tw-icpc-blog

These problems are mixed by old problems in many judge and some original problem.

You can see the last contest Weekly Training Farm #13 to understand the style of problems.

The Series contest is hosted in order to spread programming contest in Taiwan. But there are only little participants :(

As problem setters, I hope there will be more people can see these problems. So I post the blog to invite everyone. Thanks~

UPD 2: The English editorial is here.

• +194

 » 5 years ago, # |   0 The problems in the previous contests seems quite interesting and some of them i have seen here on codeforces.Can I know based on what criteria did you choose them?
•  » » 5 years ago, # ^ |   +16 I'm the problem setter from #11 to #14. Previous rounds are set by other people. If I am the setter, most problems are my new ideas. But some of them are modified from problems of other contest. For example, problem D of today is modified from ARC063 pD and problem B of today is the initial version of AGC007 pA(the contest is hosted by me). Other problems of today is my new problems.
 » 5 years ago, # |   +10 Nice problem D. How to solve E?
•  » » 5 years ago, # ^ |   +20 I only describe the outline of solution(don't contain math proving.)Assume pi is given in non-decreasing order.We have following lemma:lemma 1: We call a subarray of p is 'good' iff for any positive integer i, the sum of any (i  +  1) numbers is always greater than the sum of any i numbers in this subarray. And we can check whether a subarray good or not by only checking whether the sum of left (m+1)/2 nubmers is larger than the sum of right (m-1) numbers.lemma 2: One of the optimized solution will be keeping all numbers in some subarray of p and changing all other numbers to the ((m + 2) / 2) -th number in this subarray.lemma 3: If a subarray of p is good, then any subarray of this good subarray is also good.By the three lemma, we can fix all possible of right endpoint of good subarray and using binarysearch to find the leftmost endpoint subarray with the right endpoint. The complexity will be O(n log n).
•  » » » 5 years ago, # ^ | ← Rev. 2 →   0 Wrong answer on test case 1 following the above method. Isn't test case1 the sample1? Also, is there something equivalent to coach mode in groups contests?
•  » » » » 5 years ago, # ^ |   +5 You shouldn't print a space after the last number in the output. (I also got WA on test 1 once)
•  » » » » » 5 years ago, # ^ |   0 Thanks. Accepted. I wonder how you deduced the space thing :D
•  » » » » » » 5 years ago, # ^ |   0 Since I failed on test #1 it's clearly a formatting error, so the most obvious error is that an extra space is added. (though this should probably be mentioned in the statement)
•  » » 5 years ago, # ^ |   +5 Can someone explain their solution of D? Thanks!
•  » » » 5 years ago, # ^ | ← Rev. 21 →   +10 Code: http://ideone.com/Jstn8Z Let mx be the max(a[j]-a[i]). Then, you can notice that if for some j1>j2, there exist i1a[j1] and j2Mj if i
 » 5 years ago, # |   +5 Thanks for the nice problems! Hope there will be more of these contests in the future.P.S. How to solve E? :)
 » 5 years ago, # |   0 I'm a beginner i don't know if i'm able to practice in this training..
 » 5 years ago, # | ← Rev. 2 →   -13 .