1-gon 可爱 1-gon cute.

Hope everyone enjoy the round.

Expert, I'm coming. EDIT : it came true

Can't wait to see PinkieRabbit's performance!

Thank you for the great round!I can't wait to try my best to solve the problems!

And hope seniors can enjoy their university lives in the future!

As a tester and a fan of cute Imakf, love the round so much!
Hope everyone enjoy it!

In the last round, I passed three questions and I hope I can reach 1200 points in this round.

Wish you all wouldn't gain negative ratings in this round! (This is theoretically possible XD)

hope so (XD)

Hopefully I don't lose expert.

Respect smg23333!!!!

Wish you all wouldn't gain negative ratings in this round!

So this is unrated?

One of my curious questions： How to become a Codeforces Round tester? Sounds interesting

I can't wait to see jiangly's performance!

Today is my birthday. Hope this contest is as special as my birthday

respect++ for smg23333

You can take away my house, all my tricks and toys. One thing you can't take away, is my csgo time. ~ Iron Man

It says it is theoretically possible that no one gets negative rating.

Someone knows how?

wana to be a Specialist ... ovo ...

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Is there a way to find out if a specific user is registered for a contest (before the contest begins)?

let's see how bad I'm going to do after solving only 100 problems this year and the last submission was more than 2 months ago and the only algorithm i still remember is implentation

Edit: Well I started with C and it was a bad plan

Is this div.0?

I've checked the title of this contest for 3 times, I think this is div.1 but the problems are more like div.0.

"Wish you all wouldn't gain negative ratings in this round!" Wow!! I think all will gain negative ratings in this round XDXD

It just feels bad when i am a second year CS university student and can't solve A.

God, I felt so useless when I took that much time to solve A with solid proof, until I saw comments. Feeling so idle in this contest :)

Can't solve 2C. Lower rating :(

Капец, C легче A. Люди, как такое возможно?????

I don't know why my codes for A,B are WA

One of my worst contests ever! I will never join Chinese contests again.

The contest is not balanced. The last Div2 round was very balanced but this contest is just a fast coding contest with some sh!t.

From Newbie to Pupil to Specialist to Pupil to Newbie. What a Journey :)

There is a big gap between B and C

I am that point when there is nothing left to think about A, B, C

Every time a problem with '0' and '1' appears in a contest,

I can feel what Doremy is going through :(

Can someone give me a hint for Div2D?

A) Prove by AC, somehow works. Spent 20 mins on it, thought about rage-quitting without making submissions because it seemed like I won't be able to solve even A or B :lol:

B) Until the very end of the round I was convinved all elements also have to be distinct, so had no idea how to approach it and solved it only at the very end

C) Prove by AC, no idea why it work and whether it really works or problem just has bad pretests

D) A bit of reasoning lead to solution convincing enough. Quite a cute problem. Logic seemes easier than A/B/C

D1B editorial. Also it's my only authored problem lol.

"Wish you all wouldn't gain negative ratings in this round! (This is theoretically possible XD)", That's when we should have known that the contest would have been a disaster.

For Div1C, is this wrong or does my implementation just suck?

Let T be the MST of the graph. Since edge weights are not repeated T is the only MST.

Then a root R is good if and only if for all edges (u, v), at least one of the following hold:

• (u, v) is in T

• When T is rooted at R, u is an ancestor of v or v is an ancestor of u.

Pretty brutal contest. Very humbling, can't wait for the editorial.

Whats wrong with my code? am using PB_dS with reverse traversing and putting max value + 1 every time i check more than q

//----------------------------------<https://lnkd.in/eSDbra2>--------------------------------------
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("popcnt")
typedef long long ll;
typedef unsigned long long ull;
ll mod = 1000000007;
#define YES cout<<"YES\n";
#define Yes cout<<"Yes\n";
#define No cout<<"No\n";
#define NO cout<<"NO\n";
#define INF 2e18
#define fast_cin() ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL)
#define all(x) (x).begin(), (x).end()
#define lcm(a,b) (a/gcd(a,b))*b
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>

//----------------------------------Real game starts here--------------------------------------




void solve()
{
    ll n, q;
    cin >> n >> q;
    vector<ll> a(n);
    for (auto &x : a)
        cin >> x;
    ordered_set oset;
    vector<ll> ans(n);
    ll k = 0;
    ll ma = 0;
    for (int i = n - 1; i >= 0; i--)
    {
        if (a[i] > q)
        {
            if (k < q)
            {
                ll wo = oset.order_of_key(q + 1);
                ll w = oset.order_of_key(q);
                if (w == wo)
                    ans[i] = 1, ++ma, oset.insert(ma), ++k;
                else
                    ans[i] = 0;
            }
            else
            {
                ans[i] = 0;
            }

        }
        else
        {
            ans[i] = 1;
            oset.insert(a[i]);
            ma = max(ma, a[i]);
        }
    }
    for (auto x : ans)
        cout << x;
    cout << "\n";

}




int main()
{
    fast_cin();
    ll t = 1;
    cin >> t;
    for (int it = 1; it <= t; it++)
    {
        //cout << "Case #" << it+1 << ": ";
        solve();
    }
    return 0;
}

Div 2 A is trash

POV: no one can feel my pain The pain: 8 wrong submissions in B

Problem C is just like my friend. His name is Long. \

How can I pass problem 3？

Dear authors, shouldn't it be said in B that numbers can be equal? I love you very much, kissing you for the great time!

No more algorithm-reading problems plz No more algorithm-reading problems plz No more algorithm-reading problems plz

Ouch, the power outage plus the problems were the final nail in the coffin for me.

Sorry to say but A, B and D are one of the worst problems I ever solved. C was pretty good though.

div2c was binary search ?

what's wrong with this approach of Div2 C. Any counter testcase? It gives WA on TC 3

    for(int i = 0; i < n; ++ i){
        ost.erase(ost.lower_bound(arr[i] - 1)); // erase current element from pbds multiset

        if(arr[i] <= q){
            s[i] = '1';
        }
        else{
            int less = ost.order_of_key(q);
            int notless = (int)ost.size() - less;
            if(notless < q){
                s[i] = '1';
                --q;
                if(q == 0) break;
            }
        }
        
    }

upd: got it

Did you guys use prime factors to solve problem B? Bruteforce just got a TLE

Problems are not bad, but the problemset is too hard :(

Congratulations, you're now officially interlude 2.0

Very INTEREST Round! I have never got the place on div2 before

pC is very nice

what a shame how could I miss such a cute contest! :,c

A was torture for me.

weak pretests and lack of explanation for problem B

About how my Div1D gets FST: somehow creating a vector and resizing a vector $$$O(n^2)$$$ times magically make my code 5x slower.

I was thinking C for more than 40 mins like what exactly I could do...just read the tutorial and found that it was an easy problem :). just didn't get the right approach:(

Ratings updated preliminary. As I said here: https://codeforces.com/blog/entry/104766?#comment-932270 cheaters will be removed later.

My submission for B no problem I can not find any test case that can fail.Can anyone help me with a failing case??

Problem D https://www.codechef.com/submit/ARRAY_OPS wtf

Thanks to this contest, I had become LGM!!!

appreciate very very much for writer and tester!

my friend：“Hello！” me：“How do u know I become a Expert？”

Fortunately I miss this round(I have registered but forget ha) Only 2k solved pC Are you sure this is div2???

Anybody knows the solution for B if all ai were to be distinct between one another?

(meaning that for any l <= i, j <= r and i != j: ai != aj)

candidate master, I'm coming :>

Please don't use questions from other websites . Question d of div 2 or question b of div 1 was previously asked in codechef starters 33. https://www.codechef.com/START33B/problems/ARRAY_OPS . This gives unfair advantage to those who have seen the question previously.

why my rating is rolled back which I gained after giving this contest any help