First!

obligatory tester comment

As not a tester, it is unlikely that there will be any aliens participating in the round

I am glad to see that we can finally stop paying insane costs to keep cry's basement on Earth; rent on Mars is probably much cheaper, and we can funnel the money saved into cry's gacha addition

As a continuous supporter of chromate00, what does it mean?

As a Tester, I don't know how to farm contribution

As a tester, Chromate = Chromaid.

Wish to enjoy the problems

as a tester, i can confirm having no oxygen in basement is not fun

As a tester, I tried to pretend not to have tested.

As a non-AI user I hope I can reach to cry's basement

GLHF!

damn cry does have a basement on Mars while Elon Musk couldn't even fly to it

2.5 hours is perfect: 30 minutes solving, 2 hours staring at WA on problem C.

As a tester, I can confirm there are no problems with the problems, the test cases test cases, and the time limits limit time.

As a participant, I can ensure that when you're just a few rating behind to reach a new rank, you can't trust the authors, even if he is your friend. xD

cry should tell Elon Musk how to build basements on Mars

i think we can safely assume there will be 8 problems. if that was not the case, they would have made a 6 7 joke. right?

I liked the part with cry's basement on Mars <3

as a non-tester i think that the problems will be about space (i think so)

you will be given 7 or 8 problems what is this ?? can you tell exact no. of problems

As a tester, when did i test this?

cry Congratulations on getting a new basement on Mars. Did you have a contract with Elon Musk?

ahh, another Div3

I'm so happy to tell you that Mars is my hometown, will you send me back to my hometown and reunite with my great-great-great-great-great-great grandma?

Best of Luck everyone

When will there be cry's digital basement?

Every time you use AI in a Div3 round, a puppy dies

It's my first competition, and I hope I can get a good grade.

Can I go to mars now?

Can I take some KMnO₄, HCl and Na before I’m sent to cry’s new basement?

Can I sell oxygen tanks there for free?

Change in time?

Nice. I'll have more time to have breakfast.

what does 7 or 8 problems even mean?

One more day until Lunar New Year, and this contest is really special. Happy Lunar New Year, everyone!

I'm here to participate in order to prepare for staying up late tomorrow, when I'll watch the Spring Festival Gala from the beginning to the end......

Sieve of Eras67 , Absolute Cinema and its test case 69 420.... XD

This contest truly is Absolute Cinema

lets goo

loved the choice of numbers by authors

Mathforces !

how does ts segfault (it has smth to do with negative numbers i think but i legit have no clue (even commenting out everything other than the I/O still segfaults btw) spoiler for f btw

#include <bits/stdc++.h>
using namespace std;
#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
using ll=long long;
#define iter(i, n) for(int i = 0; i < n; i++)
#define rngIt(n, m, s) if(n>m){for(int i = n-1; i >= m-1; i-=s)}else{for(int i = n; i < m; i+=s)}
#define it(arr) for(ll i : arr) std::cout << i << ' '; cout << '\n';
#define itB(arr, a) for(int i = 0; i < a; i++) std::cout << arr[i] << ' '; cout << '\n';
#define printl(s) cout<<s<<endl;
#define MOD(a, b) ((((a) % (b)) + (b)) % (b))
#define endl "\n";
void test()
{
    int n; cin>>n;
    vector<int>a(n),b(n),c(n);
    vector<vector<int>>g(n);
    iter(i,n)
    {
        cin>>a[i]>>b[i]>>c[i];
    }
    iter(i,n)
    {
        for(int j = i+1; j < n; j++)
        {
            ll a2 = a[i]-a[j];
            ll b2 = b[i]-b[j];
            ll c2 = c[i]-c[j];
            ll disc = (b2*b2)-(4*a2*c2);
            if(disc<0)
            {
                g[i].push_back(j);
                g[j].push_back(i);
            }
        }
    }
    //ss from https://en.wikipedia.org/wiki/Maximal_independent_set#Finding_a_single_maximal_independent_set
    vector<int>ans(n);
    for(int j = 0; j < n; j++) {
        set<int> i;
        set<int> v;
        i.insert(j);
        for (int x: g[j]) {
            if(v.count(x))
                v.erase(x);
        }
        while (!v.empty()) {
            int nd = *(v.begin());
            i.insert(nd);
            for (int x: g[nd]) {
                if(v.count(x))
                    v.erase(x);
            }
            if(v.count(nd))
                v.erase(nd);
        }
        ans[j] = i.size();
    }
    it(ans)
}
int main()
{
    cin.tie(0)->sync_with_stdio(0);
    int t; cin>>t;
    iter(i,t){test();}
    return 0;
}

I felt E was much easier than D if you know basic tree.

I'm not good at math, so I realized $$$F$$$ is not a classic maximum size clique problem, and has to do something with arranging the quadratics in some way, and doing $$$O(n^2)$$$ DP, but couldn't figure out how. Had to move on to $$$G$$$ instead, where my "recursion by walking on the tree for every query" TLE'd on test 16. Sadge :(

Good problems though, thanks for the round chromate00

How can D have so many acc?

Screencast: https://www.youtube.com/watch?v=jDJe_e2jF3M

how to do pF ? I tried to build a DAG like this

auto con = [&](int i, int j) -> bool {
	auto [a, b, c] = v[i];
	auto [d, e, f] = v[j];
	if(a==d && b==e){
		return false;
	}
	return (b-e)*(b-e) >= 4LL*(a-d)*(c-f);
};

for(int i=1;i<=n;i++){
	for(int j=i+1;j<=n;j++){
		if(!con(i, j)){
			if(get<2>(v[i]) > get<2>(v[j])){
				G[j].push_back(i);
				deg[i]++;
			}
			else{
				G[i].push_back(j);
				deg[j]++;
			}
		}
	}
}

and I used DFS to get the longest chain the node at, but I got WA at test 2

There were some Einsteins on the exam.

J1_1_1 Be_ast MaxLim overlord_god

Is Binary Lifting involved in Problem G ?

How to do F?

lol..it's great problem list _great work guy,thank u!

The quality of problems is soo good here

F was a damn good problem Got to learn longest-chain and MIS in graph is a thing

SOOOOOOO MANY CHEATER HOW TO SAY THEM

TheKrrish -->look at just the codes

Adham

AbhiIron

YARISDA EINSTEINLER VAR IDI

after looking at problem A : "67" , most of time "67" meme was running in my head

Had fun. This Was the best contest till date for me.