### 21August's blog

By 21August, history, 3 months ago, ,

Last contest ( 623 div2), UnstoppableChampion was already a candidate master and he participated officially for div2 achieving 4th place and now he is a master. I guess that the ratings from the earlier contest didn't manage to update.

• -37

By 21August, history, 7 months ago, ,

Color didn't change but rating did after Codeforces Round #596 (Div. 2, based on Technocup 2020 Elimination Round 2)

• +12

By 21August, history, 10 months ago, ,

Hi everyone. Can somebody provide an working code of a segment tree that supports following operations:

1. Subtract value on suffix of array.
2. Assign a range with the smallest element in that range.

It is guaranteed that the array is always sorted in ascending order after each operation. I would like a code that implements this using lazy propagation. I tried to write such a code for the problem Jousting tournament . Here is a code of the segment tree. Also i have a function "kth" that find the last occurrence of a value in the array. The functions "up" , "push", "build" are used for this part of the problem. Please help to debug or give me another code.

• -4

By 21August, history, 22 months ago, ,

Hi everyone. I am trying to solve some of the problems from JOI. I found a very interesting one but can't understand the solution. Can somebody help me by explaining the 100 points solution. Problem link. Here you can find the solution and the code : Contest page. Thank you very much!

• 0

By 21August, history, 22 months ago, ,

Can somebody give me all the English problems he has from past JOI's because i managed to find only the 2017 contest.

• +3

By 21August, history, 23 months ago, ,

Hi, is it possible to delete my personal account?

• +2

By 21August, history, 2 years ago, ,

Hello. Suppose you have n boxes and there are a[i] balls in the i-th box. In one operation you can choose 2 balls from 2 different boxes and throw them. Is it possible to perform some number of operations such that in the end a[i] = 0 for all i? I know that the answer is yes iff a[i] <= s/2 for all i, where s is the sum of a[i]. But why is this condition sufficient? I understand that its not possible to make a[i] = 0 when a[i] > s/2, but why does this guarantee that we will be able to reach the state where all a[i] = 0? Thanks in advance.

• +13

By 21August, history, 2 years ago, ,

Today i want to say that tourist is not first on cs academy anymore. Let's take a minute to deal with this impossible loss. Um_nik congrats with being second place on CF and Atcoder and first place on cs academy.

• -29

By 21August, history, 2 years ago, ,

Hey cf crew. There is an issue in the ratings. After the last contest all the personal ratings changed but when you go on the actual rating page it remained the same. Also the names haven't changed. Hope you will fix that soon.

• +10

By 21August, history, 3 years ago, ,

Does anybody want to make a list with ejoi participant with CF accounts sorted by rating. It would be very cool to have such a list, also the rating should be updatable.

• +6

By 21August, history, 3 years ago, ,

Hi everyone. Can somebody please help me to solve this problem. Thank you very much. It is from JBOI 2015, it's called Startup.

• +2

By 21August, history, 3 years ago, ,

Hi everyone. I saw that a lot of very strong chinese contestants have solved on codeforces around 400 problems, some even 30 problems. I was wondering from where are they training because it is impossible to be that good with just 400 problems solved.

• +14

By 21August, history, 3 years ago, ,

Hi everyone. As we know this september there will be held in Sofia, Bulgaria the first European Junior Olympiad of Informatics. Here is the oficial website: EJOI. So students who were born on 31st December 2001 and younger will participate. I will also participate, even though the cometee of my country didn't announce any of it's students yet but i classified first between juniors at the team selection for IOI. It would be nice if you will post here who will participate from your country if you know that. Thanks!