We will hold AtCoder Beginner Contest 479.
- Contest URL: https://atcoder.jp/contests/abc479
- Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20261011T2100&p1=248
- Duration: 100 minutes
- Writer: physics0523, cn449
- Tester: sheyasutaka, physics0523
- Rated range: ~ 1999
- The point values: 100-200-300-400-450-500-600
We are looking forward to your participation!
surely i get A to D THIS TIME PLEASE!! good luck everybody
I still cannot understand why ABC on Sunday and ARC++ on Saturday.
I guess ARC++ or ARC-- is always on Sat., and ABC is on Sun.
ARC is always on Sun,ABC is on Sat. But it is different today.
No, I mean that:
check this
ARC232 is 第三回 AtCoder Japan Open -予選- (AtCoder Regular Contest++ 232) in Japanese. I think maybe this contest is a parallel contest of the domestic Japanese competition. As an exception, it is on saturday.
In usual, ARC-- and ARC++ is on sunday too.
I'm happy that ABC on Sunday,because I had not free time on Saturday.
Did you went school?
Yes.
Me too.
Me too!that's a bad day(I think)(loads of homework):(
hope to solve E today
hope I can solve a~d & it's not a rubbish round.
DMY student!
I hope I AC A~E!!!
i hope i can solve A to D this time.Good luck everybody i'm chinese,Chinese can fly!!!
瑨娢组织
well I solve a~d.I think c is dp at first:(
According to the rules, such information is NOT ALLOWED to be published during the contest.
Don't be sad.Learn from mistakes.It will be better next time.
in c brute force will work too!
Maybe I can do the D problem
It seems to be many chinese here...And I hope I can AC A~E
Oh no ! I got too much time on problem A!
I used ETT in E, and got a AC. is it a right solution?
what is ETT?
I don't know,but I used difference on trees to solve it
Solution discussion live-stream: https://www.youtube.com/live/v5gWDQWp654?si=f4H3FE7JQx1zFBmS
I just solved ABCDE...
I think C was the easiest problem I’ve seen in past contests.
yeah, n=20 sold the solution.
btw if n was huge and not 20, then what will be optimal solution?
i solved it using brute force and i want to know its real sol
I don't really know about solution for big n 😅 I already stop thinking when I see n=20 and do the obvious brother 🥀 .
hmm ic, literally it was js implementation, even 2^N could work ig
with a large n, it essentially becomes a knapsack problem so you need the bounds to be similar to either Knapsack-1 or Knapsack-2 from AtCoder Beginner Contest for it to be solvable.
Meet in the middle.
TYSM [:heart:]
frr all bcz of n=20, i js brute forced it
Managed to solve D in last minute, im happy. But hate problems like C, because i always want to find clever solution, instead of just checking all combinations... Or is there more clever solution?
Sure,like dp.
solved D 2 minutes after the contest :(
I had an idea for problem F during the contest,
but couldn't implement it because I haven't learnt Fenwick Tree or things like that.
Can anyone tell if my idea is correct?
My idea: Treat the net movements of all N people as vectors on the number line, pointing to either left or right.
sum up the absolute differences of all pairs of Si and Ti
subtract the number of intersecting vectors pointing in opposite directions from the answer
add back the sum of the following for each vector: the number of vectors pointing in the same direction and are completely covered by the vector in consideration, points included
Help would be appreciated a lot
I think the accept solution is segment tree,and my thought is similar to yours.
I asked Gemini to translate the Japanese editorial, and it mentions Fenwick Tree. Gemini also told me I'm correct, though I don't know how much faith to put into that
Solved A~D, stopped on E, not bad for me.
how are u all ?
Easiest G ever! My first time to complete G!