We will hold Tokio Marine & Nichido Fire Insurance Programming Contest 2026 (AtCoder Beginner Contest 459).
- Contest URL: https://atcoder.jp/contests/abc459
- Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20260523T2100&p1=248
- Duration: 100 minutes
- Writer: sounansya, math957963, YoshikaMiyafuji
- Tester: kyopro_friends, harurun4635
- Rated range: ~ 1999
- The point values: 100-200-300-400-450-525-625
We are looking forward to your participation!
I hope that I cross green in this ABC
Well, its not possible anymore :(
you can practice topic wise and difficulty wise sorting on this website to get better in future.
I hope this contest will be easy.
I hope that I can become green in this ABC.
you can practice topic wise and difficulty wise sorting on this website to get better in future.
thank you very much. I will do it if I have time.
My first ever contest in CP..
you can practice topic wise and difficulty wise sorting on this website to get better in future.
I wish i`m ak at this contest
Hope I could do ABCD
Up Score!
It's so difficult! I hope I can do ABCD.
I don't think it's that hard.
++
A,B,C,D are easy!But how E,F,G?
Actually E felt easier than other ABC contests
It was just dfs and combinatorics
Select d[i] elements from current available count c[i]
And the count of parent is increased by remaning elements from current node
Answer is zero if for any node c[i] < d[i]
But it still needs Fermat's little theorem to find the modular inverse.
Can anyone who accepted F teaches me how to solve the problem? I solved E in an hour, but i hadn't done it until the contest ends.
What's more, I think over 1/5 F-ACers used gpt.I don't believe it's easy enough for hundreds of people to solve it.
https://atcoder.jp/contests/abc459/submissions/76082942 — can someone tell what I am doing wrong here?
In Line 28,
an = (an * (c - i + 1)) % M;should bean = (an * ((c - i + 1) % M)) % M;That's why I hate the problem.
It's really more difficult than last contest.
Why Problem E examines who takes the remainder more frequently instead of the true abilities?
https://atcoder.jp/contests/abc459/submissions/76084566
I use a code to get nCr, and the rest was just some analisis I did before in the paper. I didn't have to fight against modulo, it depends on the aproach
I felt like C and D got swapped.
same able to solve d but cannot c
Yeah it was a good visualisation exercise.
https://atcoder.jp/contests/abc459/submissions/76096267 — Can someone tell me what am i doing wrong here?
Got it, I forgot to take mod while adding the extra candies back to parent. Thanks
You can use this website for Atcoder Tagged Problems along with sorting by difficulty level for practice
Read about https://codeforces.me/blog/entry/153765
nice site, much appreciated!
Problem F has weak testcases. I submitted an incorrect code to get AC. The incorrect code I used involved continuous geometry.
Example --> 1 6 2 2 3 5 6 6
Ans should be 5, i submitted two codes, one of which gives 4 as ans. Both got AC.
I think problem F is very good, and I would like to share my solution, which seems to be different from the editorial.
One of the main ideas is greedy, i.e., we stop as long as current state satisfies the requirement. The other one is as follows.
For instance, given 19 11 12 13, what should we do with 19? The process wokrs as follows.
19 11 12 13 -> 18 12 12 13 -> 18 11 13 13 -> 18 11 12 14
One can see that, the result is just like we decrease 19 and increase 13, while the total cost is 3.
Then, we go on with
18 11 12 14 -> 17 12 12 14 -> 17 11 13 14
which is again like that we decrease 18 and increase 12, with cost 2.
After one more step we would get
17 11 13 14 -> 16 12 13 14
So, the total process is 19 11 12 13 -> 16 12 13 14, with cost = 3 + 2 + 1 = 6.
We continue this and will get 16 12 13 14 -> 13 13 14 15, with cost = 3 + 2 + 1 = 6, and totally 6 + 6 = 12.
Finally, we have 13 13 14 15 -> 12 14 14 15 -> 12 13 15 15 -> 12 13 14 16.
Note that in fact, we can directly get 19 11 12 13 -> 13 13 14 15 with some simple calculation, which saves the time complexity.
By enumerating the array from right to left and implement the above method, the problem can be solved.
dear atcoder officiaL, i suspect that TangDouChaoRen19(atcoder username) is a cheater.
abc453 and abc460 are the only contests it participated in.
https://atcoder.jp/contests/abc453/standings?watching=TangDouChaoRen19
https://atcoder.jp/contests/abc460/standings?watching=TangDouChaoRen19
its performance is too weird. for example, it solved ECABFD in order in abc460 and ABCDEGF in order in abc453.
and, i suspect that TangD0uChaoRen is an alt of TangDouChaoRen19.
i hope, if they really cheated, atcoder would ban those accounts.
ABCD is easy but i made a mess on D