kingofnumbers's blog

Invitation to CodeChef May Lunchtime 2018!
By kingofnumbers, history, 6 years ago, In English

CodeForces Community! We’re happy to announce the 60th edition of your beloved three-hour coding jam. Yes, it’s time for LTIME60 for the month of May. Looking forward to having you join in the fun! Joining me this time on the problem setting panel are:

  • Problem Setter: TianyiQ (Tianyi Qiu), kingofnumbers (Hasan Jaddouh)

  • Problem Tester and Statement Verifier: Xellos (Jakub Safin)

  • Problem Editorialist: vijju123 (Abhishek Pandey)

  • Russian Translator: CherryTree (Sergey Kulik)

  • Mandarin Translator: huzecong (Hu Zecong)

  • Vietnamese Translator: VNOI Team

Contest Details:

Time: 26th May 2018 (1930 hrs — 2230 hrs). (Indian Standard Time — +5:30 GMT) — Check your timezone.

Contest link: https://www.codechef.com/LTIME60

Registration: You just need to have a CodeChef handle to participate. For all those, who are interested and do not have a CodeChef handle, are requested to register in order to participate.

Prizes:

  • Vote: I like it
  • +29
  • Vote: I do not like it

»
6 years ago, # |
  Vote: I like it +45 Vote: I do not like it

Very boring tasks.

→ Reply
  • »
    »
    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it +43 Vote: I do not like it

    I agree this month's problemset was not very interesting, we had more interesting problemsets in the past, the issue is that we didn't have any proposal for this month's lunchtime so I had to set those problems in short time and I couldn't find problems more interesting than those problems within available time.

    so I would like to invite anyone who has interesting problems in mind to propose a problemset for short contest (cookoff — lunchtime) to us via email problems@codechef.com.

    → Reply
»
6 years ago, # |
  Vote: I like it 0 Vote: I do not like it

In problem SBSTR some solution with complexity O(n*n*26) also passed.

→ Reply
»
6 years ago, # |
  Vote: I like it 0 Vote: I do not like it

please explain the approach of SBSTR ..

→ Reply
  • »
    »
    6 years ago, # ^ |
      Vote: I like it +1 Vote: I do not like it

    for every sub-string keep track of frequency of its characters , and no of distinct character and and max frequency of character. For string to interesting no of distinct chars should be greater than k and (max freq)*(no distinct chars) should be equal to length of sub-string.
    see this solution by tourist https://www.codechef.com/viewsolution/18660725.

    → Reply
»
6 years ago, # |
  Vote: I like it +16 Vote: I do not like it

Problem TSUM2 subtask 2, I got WA and RE. Is there a longer path than 200 nodes?

→ Reply
  • »
    »
    6 years ago, # ^ |
      Vote: I like it 0 Vote: I do not like it

    I got WAs both in first and second subtask. Possible I have bug, but also it is possible they have longer path (I have only 2 AC in the first subtask too, but I believe binary tree can have any depth).

    → Reply
  • »
    »
    6 years ago, # ^ |
    ← Rev. 2   Vote: I like it 0 Vote: I do not like it

    I am actually the setter of problem TSUM2

    Sorry, It is totally my fault.

    I made several mistakes when generating the tests.

    This is the first time I've set a problem. I feel so guilty that my carelessness causes such terrible issue. Apologize to everyone who got stuck on this problem.

    → Reply
»
6 years ago, # |
← Rev. 2   Vote: I like it 0 Vote: I do not like it

For the last one.Is the idea doing dsu on trees + 2 dynamic convex hull tricks and maintaining some deficits while updating convex hulls(something like Venice technique).

UPD: My idea works though editorial describes centroid decomposition

→ Reply