As a tester, this is my first "as a tester" comment.

Since we all know real Codeforces rating is actually determined by rating * contribution, as a writer, give me contribution.

As a tester, the contest is very good and I like all the problems!

Also, orz myst-6

as a tester, i swear on skippity problem F can be solved by binary searching a segment tree and morphing the result into a dsu before finally getting the answer using a mixture of crt and fft (alternatively you can use a persistent 1729-dimensional convex hull trick on a sparse segment tree)

Also, orz myst-6

As a tester, do not miss the contest.

Love the photo! Who are the other mysterious coders in it? One of them has a blank screen. We need to know :)

As a tester, just put the contribution in the comment bro

BucketPotato orz

Another quick chance to re-perform after all these greedy pains and hacks on map... Hope to reach pupil again this time

Last year I made the same question and still don't know why to make a contest on Ieeextreme day T~T Ik maybe it's not on clist but most of coders know about ieeextreme and its date. Anyway, Thanks authors for a new round ^-^

I am the camera

Whats (1250 + 1000). Can someone explain?

LongTrainDiv2

As a tester, I love the problems! ＼(＾▽＾)／

Also, orz myst-6

wtf these guys look too chad to be studying cs

As a tester, I can confirm that problems have statements

clashes with lc biweekly

should I give cf div 2 or leetcode biweekly?

this is a really good practice of keeping the photos of people preparing the contest, it gives good vibes + i personally feel that yes in today's AI world still there is human interaction which makes me happy.

As a tester, I've purchased this contest for kids' enjoyment.

First CF after AFO.

CSP rp++ (CSP: a very important contest for Chinese OIers, just ended 30min ago)

Guys you giving LeetCode Biweekly or, Codeforces Div 2? Imma confused :(

myst-6 fasrsi baladi?

Is there gonna be a hacking phase?

Good Index.

hope i become specialist after this round :)

why is contest registration closed before the start?

Oh, speedforces today!

Any hints for E1? I feel like the nimber for each pile should only be revolving around $$$\text{popcnt}(x_i)$$$, but I hardly came up with anything...

Wasting 40min thinking about E1 while I could have been coding D2 should be one of the worst tactical decisions I've ever made XD

so close to solve C but failed...

Oh! Because I wasn't familiar with discretization, I lost a lot of ratings in this round.꒰╬•᷅д•᷄╬꒱

How do you solve C ? I couldn't solve it no matter what

Alright, so how to count the number of ways to achieve the result in D2? Struggled for an hour and still didn't get past TL8 (all other ideas just WA-ed).

How do you do C? I tried a graph solution but it was too slow.

i got so confused on B, worst performance in a while. i found C pretty cool, and D1 seems doable, but i just wasted too much time on B. nice round

hints for D1??

How to solve A? Really do not understand why my solution was wrong.

Awesome B. Cost me 1 hrs + 3 WAs. That B is fucking hard, C is much easier. I think D1 is easier than B, but I have no enough time to solve it.

wtf was b's solution? I know im sleep deprived, but im felling dumb af

I printed lots of pairs $$$(n,k)$$$ on problem E1 and try to guess answer, it takes me 2 hours, just for 1000 points?

As a newbie, I am just never able to solve B (crying emojis)

Problems A, B and C were pretty good, but D1 is too easy. It is a really standard DP problem. Also speedforces.

All dp? Solved B, C, D1 with dp.

How to solve E1? My code is timing out when computing the SG function. Can someone help me?

#include <bits/stdc++.h>
 
#define int long long
 
constexpr int N = 1e5 + 6;
 
int mex(std::set<int> &s) {
  int m = 0;
  while (s.find(m) != s.end()) ++m;
  return m;
}
 
std::map<std::pair<int, int>, int> mp;
 
int SG(int x, int a) {
  if (x == 0) return 0;
  if (a >= x) return __builtin_popcount(x);
  if (mp.count({x, a})) return mp[{x, a}];
  std::set<int> s;
  int d = x;
  while (d > 0) {
    if (d <= a) {
        s.insert(SG(x - d, a));
    }
    d = (d - 1) & x;
  }
  return mp[{x, a}] = mex(s);
}
 
void solve() {
  int n;
  std::cin >> n;
  std::vector<int> a(n + 1, 0), x(n + 1, 0);
  for (int i = 1; i <= n; ++i) std::cin >> a[i];
  for (int i = 1; i <= n; ++i) std::cin >> x[i];
  int ans = 0;
  for (int i = 1; i <= n; ++i) ans ^= SG(x[i], a[i]);
  std::cout << (ans ? "Alice" : "Bob") << "\n";
}
 
int32_t main() {
  std::ios::sync_with_stdio(0);
  std::cin.tie(0), std::cout.tie(0);
 
  int t;
  std::cin >> t;
  // t = 1;
 
  while (t--) {
    solve();
  }
 
  return 0;
}

I don't understand why B's constraints are low when a non-n^2 solution is not hard to do and fits a div2 B. (Yes, I am annoyed that I didn't look at the constraints, which is totally my fault).

couldn't solve B

I'm screwed

For B I was trying to get traverse till the first decreasing slope (i,e. traverse till A[i] < A[i+1]). And then my peak would be A[i]. Any number greater than this peak also is to be deleted. This failed on pretest(3). So I would love new ideas ?

288174453 When I submit D2 at the last minute:

Passed pretests 1-7 ... :)

MLE in 8 :((

Lesson: use vectors to handle DP with uncertain array lengths ; )