We will hold Denso Create Programming Contest 2026（AtCoder Beginner Contest 443）.
- Contest URL: https://atcoder.jp/contests/abc443
- Start Time: http://www.timeanddate.com/worldclock/fixedtime.html?iso=20260131T2100&p1=248
- Duration: 100 minutes
- Writer: sounansya, physics0523, kyopro_friends, ynymxiaolongbao
- Tester: MMNMM, math957963
- Rated range: ~ 1999
- The point values: 100-200-300-400-450-525-575
We are looking forward to your participation!
Hope everyone good luck!
Hope everyone good luck!
non-sense input
Codeforces is really strange. Last time I saw someone say the same thing as you, but got downvoted.
Four Language Ver.
Good Luck! Удачи! 幸運を！ 好运！
Bonne chance!
Happy winter break！
Good luck and happy winter break!
Hope everyone good luck! Happy winter break!
What a nice day! Good luck to everyone!
I was hard stuck in building up logic for D.!
Can Anyone explain me the problem E?
You assume Takahashi can split into three in one move. And you prove one Takahashi doesn't rely on others. So you can do it from down to up just once.
Current point is (x, y). To check (x, ny), included the case if coulumn ny is ever reached.
It's like a BFS, start from $$$(n, c)$$$, and visit as many points as you can. If the destination point $$$(r, c)$$$ contains
#, just check if all points below $$$(r, c)$$$ are either.or were reachable (you can do this by maintaining a simple count). The BFS queue for row 1 is the answer.Good problems. Is $$$F$$$ digit DP? But what is the upper bound on the length of the answer? And when is the answer -1?
Answer becomes -1 if N % 10 == 0, because if n divisible by 10 then it ends in digit 0, so all digits before it must be greater or less or equal than 0 because the sequence is non-increasing from left to right. This forces every digit become 0. But since n needs to be positive number, no solution exists.
Problem D was very similar to Codeforces "Nusret Gokce" https://codeforces.me/problemset/gymProblem/104114/N, just that m = 1.
I was getting WA on F initially, and got AC after outputting -1 whenever my BFS did not find a value. My initial condition for there being no answer was that N was a multiple of 10. Can someone give an example of a value of N that isn't a multiple of 10 with no answer?
275
Here is list of N values I found, where N is not multiple of 10 but still have no answer.
625, 825, 925, 1375, 1616, 1875, 1925, 2275, 2475, 2525, 2775.
Limits seemed really tight on the D problem. Even NlogN complexity soln of mine was given a TLE. I used a djikstra style algo on a "line graph".
My solution
https://atcoder.jp/contests/abc443/submissions/72932125
Time limits are really tight on F! (especially for python)
Can anyone help me out on why my solution to E is giving WA?
https://atcoder.jp/contests/abc443/submissions/72940239
I have just checked if the lowermost wall for each column is destroy-able, then all the walls of that column are destroy-able, then i just destroy all the walls which are eligible and run a simple BFS from source.
As far as i can see, the Editorial solution also destroys all the destroy-able walls, and the concepts seems similar.
EDIT1: This one is also the same submission but using DP instead of BFS https://atcoder.jp/contests/abc443/submissions/72944003
I made the same mistake
Consider this counterexample
The issue is that you assume that as long as the lowest hash of some column is above the first cell reached from the source we can destroy in that column.
But here, In column 2, in order to destory the hashes, we need to reach cell in row 3, but that's not possible because the path to that goes through walls that cant be destroyed.
Thank you, i got it, Sorry for late reply, i didnt open cf for a long time.
Problem G.
1. I think the addition of $$$1$$$ that makes the equation <= instead of < is simple and intuitive but I just can't understand it. Can someone please elaborate on it?
2. Why adding $$$1$$$ is beneficial?
3. Are there some other problems that requie floor-sum so I can practice it?
Thanks.