Dear Codeforces community,
We are excited to invite you to TOKI Regular Open Contest (TROC) #13!
Key details:
- Contest links: Div 1 (rating ≥ 2000) and Div 2 (rating ≤ 1999)
- Time: 14 June 2020, 21:05 UTC+7
- Writers: yz_ rama_pang steven.novaryo
- Duration: 2 hours
- Problems: 5 for every division
Scoring distribution:
- Div 2: 100 — 200 — 300 — 400 — 500
- Div 1: 100 — 200 — 300 — 500 — 500
We would like to thank hocky, fushar as organizers, rapel, jt3698 as testers, and Yoshiyuki as proofreader.
Please register to the contest, and we hope you will enjoy TROC #13!
UPD1: We postponed the contest by two hours so that it no longer clashes with AtCoder
UPD2: Contest is over! Our top 5:
Div 1:
Div 2:
Editorial is available here (English on page 8).
You can upsolve the problems here.
Thank you for participating and see you on the next contest!
Woah, a TROC that doesn't conflict with other contest sites? This is rare.
Hopefully I didn't just jinx it.
Welp, nevermind.
Look what you have done? Now it clashes with Atcoder Beginner contest 170!
Jinxed
:)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
(read: visible depression)
looks fine :')
bruh why did you have to say that
Is it rated?
Yesssss!!!! I've been waiting for this >:D
Would you consider rescheduling it as it conflicts with the ABC contest?
We decided to postpone the contest by two hours.
Thank you sir!
Auto comment: topic has been updated by prabowo (previous revision, new revision, compare).
Friendly bump, the contest starts in 3 hours!
We hope you enjoy our contest and problems!
This contest starts in 20min.
How tf is neal, tourist, zscoder, maroonrk, yosupo etc. in div2...
Auto comment: topic has been updated by prabowo (previous revision, new revision, compare).
Can someone prove or at least tell why, in problem Div1C it must hold p % c == 0?
C is the number of nails that will become a part of the polygon, alternatively the number of vertices of the polygon. A polygon that has C vertices have C edges. Since we want a regular polygon where each side has the same length, the perimeter must be divided into C exact parts, thus the perimeter must be divisible by C.
What do you mean by this? In what way can this be visualized? We just came to the conclusion that a regular polygon with integer length sides and an integer length perimeter must necessarily have a perimeter divisble by c, but why?
In Euclidean geometry, a regular polygon is a polygon that is equiangular (all angles are equal in measure) and equilateral (all sides have the same length). - Wikipedia
Since it is equilateral, therefore a regular polygon with $$$C$$$ vertices must have perimeter of length $$$C \cdot S$$$ where $$$S$$$ is an integer (since the length is an integer). Therefore, the perimeter must be divisible by $$$C$$$
Therefore, when looking for the answer with $$$C$$$ vertices, one must first find the $$$S$$$. Afterward, we are then required to determine if the circular array can be into $$$C$$$ parts where each part is of length $$$S$$$.
Yeah, this is the part the is making trouble for me. Why exactly does this held true just cause all the sides are of equal length? Is this really that obvious because I still don't see it lol.
Actually, what if you have a regular polygon with 6 vertices and a side length of, say, 2. The perimeter of this polygon is 4 (the perimeter is (side length / sin(180degrees / n) = 2 / sin (30) = 4).
Side length is the length of a side. A polygon with 6 vertices has 6 sides. If each side has length 2, the length of all the sides (also known as the perimeter) would be 2+2+2+2+2+2=12. As you can see, 6 is one of the factors of 12.
Yeah, I misunderstood stuff, thought the perimeter was 2 * radius and didn't see that the arches were given instead of distances between points... Thanks.
Amm I misread and misunderstood everything hah, I thought the perimeter is 2 * r while it's the path around a polygon and I thought that the distances between points are given and not the arches... Thanks.
Actually, what if you have a regular polygon with 6 vertices and a side length of, say, 2. The perimeter of this polygon is 4 (the perimeter is (side length / sin(180degrees / n) = 2 / sin (30) = 4).
Amm I misread and misunderstood everything hah, I thought the perimeter is 2 * r while it's the path around a polygon and I thought that the distances between points are given and not the arches... Thanks.