The ICPC WF 2025 is set to take place in Baku, starting on August 31th(just around 9 days to go),

Who will rise to the top this year?

Comment your predictions below!

UPD:ONLY 4 DAYS REMAINING!!!!

The IOI 2025 is set to take place in Bolivia, starting on July 27th(just around 13 days to go),

Who will rise to the top this year?

Comment your predictions below!

P.S. You can see Teams in this blog post: Otherwordly's blog

UPD:ONLY 2 DAYS REMAINING!!!!

suggest a problem to solve as my 1400-th problem in CF

If you want to post an entry PLEASE PLEASE PLEASE first search and see old blogs maybe someone have already asked your question. If all users do this, there won't be too much blogs like "how to become expert" or something like that.

Contests are getting pointless and all results are almost unofficial because of cheating and AI.

I hope someone do something for this :(

codeforces works like this:

1.start the contest go to line 2

2.is tourist winner? if Yes line 3 else line 1

3.finish the contest

Tourist level has still the same color as LGM in the chart:

You can make a mashup contest of problems you want to solve and send your solution in a group. Your code will be judged in a few minutes!

I tried a greedy solution for this problem:
1. If there exist a pair of adjacent vertices like $$$(u,v)$$$ such that $$$deg(u)\geq3$$$ and $$$deg(v)\geq3$$$, then remove the edge between $$$u$$$ and $$$v$$$.
2. Then, if there exist a pair of adjacent vertices like $$$(u,v)$$$ such that $$$deg(u)\geq3$$$ and $$$deg(v)\geq2$$$, then remove the edge between $$$u$$$ and $$$v$$$.
3. Then, if there exist a pair of adjacent vertices like $$$(u,v)$$$ such that $$$deg(u)\geq3$$$ and $$$deg(v)\geq1$$$, then remove the edge between $$$u$$$ and $$$v$$$.
At last, I add edges between the leaves of different components .
Why isn't it correct??

submission

Given a graph G s.t. any cycle in G has length 3.
1)Find the maximum number of edges. 2)Find the maximum number of cycles.

How to find the number of pairs of integers (x,y) such that gcd(x,y) = 1?
n<=1e6
x<y<=n
time limit = 2s