Hi, that will be my first contest. Anyway, good luck everyone.

hahaha!

Good luck!

Gave the contest. It was good. When and where can I find the editorial for this contest ?

What a big difficult gap between F and G.

I solved 5 problems. Got confused on problem E for a long time...

is E sweep line ?

Happy New Year! And it's a great contest as a gift for 2026, because A~F are very easy and G is challenging for advanced contestants.

Great contest! I solved 5 problems.(A — E)

got 3 WAs on B because I forgot that YES is not Yes ;((

I really have to start getting more used to early morning programming...

E was such a pain, I recognised LIS — knew had to handle consecutive same elements somehow.

I only tried with sorting in increasing a and then increasing b.

Editorial shows answer breaking ties by decreasing b?

In case anyone got 5 wa in E (Kite) like me, consider following testcase: 5 1 1 2 2 3 1 3 2 3 3 expected ans: 3 and not 2.

If we have an array $$$P_0, P_1, P_2, \dots, P_N$$$, how to compute $$$\sum_{t=1}^{N}(1 - P_t)^{i - 1} \cdot P_t \cdot (1 - P_{t - 1})^{L - i}$$$ for each $$$i$$$ from $$$1$$$ to $$$L$$$ fast?

Original problem for E:https://www.luogu.com.cn/problem/P2782

This is what G made me think:

why getting wrong answer on 3rd

int t=1;
    while (t--) {
        int n;
        cin >> n;
        int i=1;
        vector<int>ans;
        int cnt=0;
        for(int i=1;i*i*1ll<=n;i++){
            for(int j=i+1;((i*i*1ll+j*j*1ll)*1ll)<=n;j++){
                ans.push_back((i*i*1ll+j*j*1ll)*1ll);
            }
        }
        sort(ans.begin(),ans.end());
        // cout<<ans.size()<<endl;
        // help(ans);
    }

I solved E but my solution was surprisingly complex for E. Segment tree + input compression + sweep. I read that some people solved it with LIS. Do you mean actually reducing the problem to LIS or did you implemented a similar solution to LIS but maintaining best sequences for 2 types. Those that ends on a segment directed in bottom-right and those directed to top-right?

gl & hf!