Hope I can get back to the blue in this round!

UPD: I will try again =)

Hoping for a good contest！

Hoping to lock in the day of the round! First this Codeforces round then Teamscode! Good luck to everyone on all of the contests!!!

First reaction: wow the plush pine tree is so lovely, but I can't reach the top 30 :(

Then, after some searching: omg it could be found in amazon.

As a tester, I tested the round.

Very nice round. I am a little bit upset because I tested so I could not participate officially.

As a participant, hope everybody good luck and win lots of pines!

Hope I can reach pupil :)

Guys, scoring distrib pls pls pls

All the best Guys:)

As testers, jiangbowen and I tested the round.

This round will contain some really challenging problems ig :)

As a participant, I will participate in the round.

potato

I really want to be a specialist, hope to get a positive delta :)

first contest as a pupil, hoping for specialist after this one!

Hope I can solve 4 problems!

Every time I see any Chinese coder from Zhou dynasty my mind reads Zhou Guanyu (avg F1 fan me :-))

Scoring distribution when?

I hope to learn more from this round of competition

Stop interactive problems :(

I have a question There is an indicators array of size n and corresponding profit array of size n. We have to select indicators in such a way that their bitwise or is <= k while maximising the profit. n<=1e5 k<=2^30 indicators[i]<=1e9 profit[i]<=1e9 Can someone provide an algo?

speedforces loading...

Hoping to become green after this round

nob nob

пон, надеюсь, решу много SergeevAmogus

tourist will win this round : )

Too difficult for me :(

Staring at D for 2 straight hours

Why so many boring detail Problems ???????
There's no interesting idea in A-F !!!
ARE YOU CREATING CHINESE COLLEGE ENTRANCE EXAM'S MATH PROBLEMS ?????

the best guess I made in C is that the best next step is x = sum of array / size of array

it seems to work but I'm getting wrong on test 2 so it's maybe not optimal

Can someone please tell me what is wrong with this solution for problem E. If the graph is bipartite I play as Bob and just greedily color the graph, otherwise I play as Alice and spam "1 2"?

I hate constructives so much now

To continue the streak of "unconventional solutions", now with today's D:

• If $$$n \le 6$$$, copy sample outputs.
• If $$$n > 6$$$, output 1 2 3 4 1 2 3 4 ...

Pretty much the same problem as E: 1503B - 3-Coloring though it's probably just a coincidence.

Regardless, I really enjoyed the round!

D is the worst problem I've ever seen in my life.

Here's my thought process for C: Absolute Zero.

$$$10^9 < 2^{30}$$$. Therefore, either the constraints are bluffing and the optimal number of moves is very small (like 3-5), or the solution involves some binary searching like idea (where you keep on trimming the range in half).

Even if the constraints are a bluff, let's explore the binary search idea. If they want you to trim the range in half, what happens when you select the midpoint of $$$[0, 10^9]$$$ as the first $$$x$$$. Notice that every point can be at a distance of $$$mid$$$ on either side. Therefore, the maximum array element has been reduced by at least half. If you repeat this process 30 times by taking midpoint of $$$[0, max]$$$ (and let's do it 39 times instead just to be sure), then at the end, the array would contain identical elements. So you can use the last operation to subtract that identical element to convert it to zero.

Code

How to solve problem D?

The rough approach for E and F felt way more obvious to me, I've got zero intuition for D after trying it for 30+ mins.

D much harder than E??? I stare D at 90min, while I spend 15min solving E.

[deleted]

how it feels to have no idea what the solution for D is after 2 hours of solving it:

F: Ancient Japanese knowledge is now blooming...
UTPC2011-G

Why is k = 1 and k = min(n,m) allowed in the input for G? It's just more stupid casework...

EDIT: Looking back i was just salty. The problem is fine, my code was just impossible to debug. Just recoded it today and it worked relatively quickly

Few samples for harder problems!

Problem E has only two samples with $$$n=m$$$, so when I made a mistake in my code(it plays $$$m$$$ rounds instead of $$$n$$$), it passed the samples and got wrong answer on test $$$2$$$! Spent two minutes staring it out.

Problem F,G both have only one sample??

For problem F, here's one similar problem (similar trick) on luogu, and it's in one of the recent contests.

For problem E, can anyone explain why 273228602 fails on Test case 1 (second test), even if my output matches for second test matches with the output given in the problem statement.

Code Link

Can someone give me a hint for D (not the solution)

hey Tourist why you so smart,

the way you solve problem is just pure art.

How are you so fast

You come first, I come last.

Problem E is a repeated problem Original Problem

n=1 on E was hell to debug for 2 hours, this is the worst i've tilted since this round lmao

ConstructiveForces

A<B<C<E<F<D ???

GuessTrickForces :(

Thank you for the round!

what was C? and why am i getting WA in this

Poor experience

Feeling quite retarded , not able to get old form back. That's the thing with CP... if we stop practising. Performing in contest is a different skill. Anyways CP is best.

G is a great challenge to the player's guessing ability. But I don't like it. ()(())

This Round is the worst round i have ever seen

Where is $$$998244353$$$? X(

The fact that both H and I are solvable surprised me a lot. Strange feeling. Thanks for the preparing the round!

Thanks for the round! Maybe the best round in this year!

I really hate problem of D kind

guess until get it right

interesting constructives early on.

can some one tell the reason for problem C approach or what is your thinking process

humorous problem D

Thanks for speedforces and cool problem G, enjoyed the round!

A sample test with $$$\min(n,m)=k<\max(n,m)$$$ wouldn't hurt in G. Very silly bug.

ZhouShang2003 Is there any issue with problem E? I was getting WA in pretest1 but now it is accepted?

is there some bugs in judging system of prob E? Somehow my E become AC after the contest ?

Human intelligence round

Is upsolving restricted now??

if you submit a wrong solution for a task and you never submit a correct one, will you still get the penalty?

#include<bits/stdc++.h>
using namespace std;

#define ll long long
#define pb push_back
#define all(x) x.begin(),x.end()
#define FastIO ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);

const ll N= 1e5+5;
ll val[N];
bool vis[N], chk;
vector<ll> even,odd;
vector<ll> adj[N];

void dfs(ll u){
   vis[u]= 1;
   if(val[u]==0) even.pb(u);
   else odd.pb(u);
   for(ll v: adj[u]){
      if(vis[v]){
         if(val[u]==val[v]) chk=0;
         continue;
      }
      if(val[u]==0) val[v]= 1;
      else val[v]= 0;
      dfs(v);
   }
}

int main(){
   FastIO;

   ll T=1; cin>>T;
   while(T--){
      ll n,m; cin>>n>>m;
      for(ll i=1;i<=n;i++){
         adj[i].clear();
         val[i]= 0;
         vis[i]= 0;
      }
      odd.clear(); even.clear();

      for(ll i=0;i<m;i++){
         ll x,y; cin>>x>>y;
         adj[x].pb(y);
         adj[y].pb(x);
      }
      // val[1]= 0;
      chk=1;
      // dfs(1);
      for(ll i=1;i<=n;i++){
         if(!vis[i]){
            val[i]= 0;
            dfs(i);
         }
      }

      // for(auto it: odd) cout<<it<<' '; cout<<endl;
      // for(auto it: even) cout<<it<<' '; cout<<endl;

      if(chk==0){
         cout<<"Alice"<<endl;
         for(ll i=0;i<n;i++){
            cout<<1<<' '<<2<<endl;
            ll x,y; cin>>x>>y;
         }
      }
      else{
         cout<<"Bob"<<endl;
         ll oddl= odd.size(), evenl= even.size();
         ll oo=0,ee=0;
         bool ooo=0,eee=0;
         for(ll i=0;i<n;i++){
            ll x,y; cin>>x>>y;

            if((x==1 || y==1) && oo<oddl){
               cout<<odd[oo]<<' '<<1<<endl;
               oo++;
               if(oo==oddl) ooo=1;
            }
            else if((x==2 || y==2) && ee<evenl){
               cout<<even[ee]<<' '<<2<<endl;
               ee++;
               if(ee==evenl) eee=1;
            }
            else if((x==3 || y==3) && ee<evenl){
               cout<<even[ee]<<' '<<3<<endl;
               ee++;
               if(ee==evenl) eee=1;
            }
            if((x==3 || y==3) && oo<oddl){
               cout<<odd[oo]<<' '<<3<<endl;
               oo++;
               if(oo==oddl) ooo=1;
            }
            // else if(ooo){
            //    cout<<even[ee]<<' '<<3<<endl;
            //    ee++;
            // }
            // else if(eee){
            //    cout<<odd[oo]<<' '<<3<<endl;
            //    oo++;
            // }
         }
      }

   }
   return 0;
}
/*

*/
/*

*/

why it is wrong ?

idea: odd cycle: alice else
even level fill by 0 and odd level fill by 1. if any level full others level fill by 3.

E was amazing!

nice contest

This round wins the "Cutest prizes" title

construct, construct, construct...

Can anyone help me find out why my 273201975 on 1991E - Coloring Game received a WA verdict, Checker comment is "wrong answer Integer 3 violates the range [1, 1] (test case 19)" :)

Update: I figured it out with the coordinators. It seems that most people affected by this are already taken cared of, it is just that most code ends in WA and I got hit with TLE so it was missed.

ZhouShang2003 I am having the same issue in problem E.

TLE during contest (50+ of them) AC after contest, codes identical.

TLE code in contest: 273157246, AC code resubmission 273253391. Please check that the code are identical.

Please look into the situation,

Far more importantly, please clarify what made the differences and so I can avoid running into it again: If the interactors or test case 1 had been changed between the contest and after systest.

Plus please consider un-rating the affected people. I lost at least 30 minutes and all my momentum and mood, (in fact I think I would have gotten at least a moderate positive delta without this).