Hello,

Can anyone share a polygon of n vertices generator (not necessarily convex) , and validator, its best if it was used in a previous CF round.

Solution

Solution

Solution

Solution

Solution

Hello codeforces!

I'm glad to announce that codeforces round #478 for the second division will take place on Tuesday, May 1st 17:05 MSK. First division participants can also take part out of competition.

Great thanks to Nikolay Kalinin (KAN) and Fudail Hasan (fudail225) for helping me prepare the contest, to Mike Mirzayanov (MikeMirzayanov) for the great Codeforces and Polygon platform, Many thanks for Amr Mahmoud (RetiredAmrMahmoud ) Tameem Zabalawi (timo14z), AmirReza PoorAkhavan (Arpa), Alexey Ilyukhov (Livace), Hag Ahmad (Reckt), Nikita Bosov (FalseMirror) and Andrew Rayskiy (GreenGrape) for testing the round.

You will be given five problems and two hours to solve them. The scoring distribution will be published soon. Good luck everyone!

I hope you'll enjoy my round. I wish everyone good luck and high rating!

UPD1: problem scores: 500 — 1000 — 1500 — 2000 — 2500

UPD2:

Congratulations to the winners

1- kmjp

2- TangentDay

3- Llamap.

4- E869120

5- kevinsogo

Div.2 winners:

1- Llamap.

2- amarDhcuMoS

3- phongthan

4- Nirma_Sucks

5- MagolorSoul

UPD3 : Tutorial is out!.

What are the greatest programming tips and tricks you have learned on your own by years of coding? ****

For me, These are the most important tips I can really think of.

1) Keep it simple.

Spend a while planning ahead to save countless hours of frustration, headaches and failure.

2) TEST in every sub-problem your code solves.

I think this tip is for non professional coders such as myself, because when you move on to the next sub-problem you save your self the time of rereading what you have checked before (you check the last part of code to detect the bug in your code). Trust me this doesn't take much time just 50 seconds after each sub-problem.

3) Readability is more important than most believe.

When you learn to write simple readable code, you can code faster. The bugs will not occur as a messy code and if a bug occurs it will be faster to detect it and fix it.

Please share your experience, and correct me if I am wrong!

Hey there Codeforces!

Anyone knows problems on SCC/bridges please drop'em in the comments!

thanks in advance.

80D - Falling Anvils

This was a nice survey problem! during my virtual participation I solved it using ### calculus and ### graph analysis.. this method is very efficient and fast to solve problem this type.. so I wanted to share with the CF community!

the probability with which an aim can be successfully hit by an anvil is the probability of choosing a (p) factor times the probability of which we can choose a valid q factor that can make the hit successful!

the probability of choosing a random p is dp/a, the probability for a valid hit for a given p is q/(2*b)

Hey there, I am new on codeforces and I wanna train, therefore I might represent my country in the upcoming ACM or even ICPC. I felt like there is a gap between the B and C problems difficulty, most contests I viewed, problems numbered A ,B were very easy, however problems C, D, & so on were very difficult. I may think that this is the point I cannot pass , because I want to train on medium difficulty problems , what do you suggest? codeforces!

UPD1 I have improved a lot since last year! It was accomplished by studying many algorithms such as in Graph(dfs, bfs, dijkstra, topological sort) and in divide and conquer such as (dynamic programming, binary search) and data structure ( segment tree, trie, prim, BIT..). you can search Youtube for good tutorials for these algorithms/data structures. even though problems div1D div1E... still are very difficult.