are technocup rounds rated ?
can someone tell rules of these rounds?

with "with ratings up to 1600" so me a 380 rating can participate right?, sorry this is my second contest still a noob, is div 3 problems easier than div 2 last time where I participated?

<too-old-joke-about-copy-pasted-part>

Note that the penalty for the wrong submission in this round (and the following Div. 3 rounds) is 10 minutes. Can anyone explain how this penalty is calculated?

What does it mean by -"I tried to make strong tests — just like you will be upset if many solutions fail after the contest is over." Are the pretests too weak or are they strong enough so that there would hardly be changes in the accepted solutions before and after the contest in the main tests?

My rating is 1603, is this round rated for me? base on description I am a "trusted participant of the third division", but I don't understood It is rated for those who have rating lower than 1600 "and" the trusted participant of the third division or just for first group.

Hope no long queue :>

Hello! I have got a question: do pretests too light to catch wrong solution? Why another person has an opportunity to make tests, which will "kill" solution of the problem?

how to register for this? this will be my first one

no side story ?

rating has taken a major dip :(,hope to improve it in this round

During my school time :(

No worries better luck with next div.3 contest

Really waiting for Div3..

Let's hope this time finally I am able to break the 1599 barrier after falling back from 1590+ rating many times

Can someone please tell me why is there a trusted participant definition created when the contest is rated for non trusted participant too. Is there a difference beside the official standing table or anything i am missing?

what is the fastest set solve for div3? william lin did today in 23 minutes!! that's just amazing!!

.

How to approach problem E ?

Is Y coordinate of any use in E?

B solution please?

Was E solvable with two pointers? I tried so but getting WA on test 2.

int n, m, k;
int a[N], b[N];
void solve(int test_case){
	int i, j;
	cin >> n >> k;
	for(i=0;i<n;i++){
		cin >> a[i];
	}for(i=0;i<n;i++)cin >> j;
	
	sort(a, a+n);
	int r = n-1;
	for(i=n-1;i>=0;i--){
		int R = a[i]+k;
		while(r>0&&a[r-1] > R)r--;
		b[i] = r-i+1;
	}
	b[n] = 0;
	r = 0;
	int ans = 0;
	for(i=0;i<n;i++){
		int R = a[i]+k;
		while(r+1<n && a[r+1] <= R){
			r ++ ;
		}
		ans = max((r-i+1) + (b[r+1]), ans);
	}
	cout << ans << '\n';
	return;
}

Providing testcase would be great help

Great contest. Thanks vovuh

Help me with E and F

Idea behind F?

Very nice problems. Solved all but F (WA39). Any ideas about F? Maybe some dp? Greedy didn't work

How to pick the two segments in E after coordinate compression? Will greedy work?

I think there is a tricky edge case in problem D

can anyone help to solve 2nd question?

.

Can someone pls tell what was wrong with my D? https://codeforces.me/contest/1409/submission/91874703

Problem E: you(y coordinate) vs the guy(x coordinate) she tells you not to worry about.

E was nice!

Useless cheating, but still

#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define ld double 
#define rep(i,a,b) for(ll i=a; i<b; ++i)
#define BOOST std::ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define pb push_back
#define all(v) v.begin(),v.end()
#define sl(a) a.size()
#define mod 1000000007 
#define lcm(a,b) (a*b)/__gcd(a,b)
#define MAX1 100006
#define f first
#define s second
#define pi 2*acos(0.0)
bool isPowerOfTwo (int x) {  return x && (!(x&(x-1)));  }  
void solve()
{
    ll a,b,sum=0; cin>>a>>b;
    ll x=abs(a-b);
    for(ll i=10; i>=1; --i)
    {
        if(i<=x) 
        {
            sum+=(x/i);
            x-=((x/i)*i);
        }
    }cout<<sum<<"\n";
}
int main()
{
    #ifndef ONLINE_JUDGE
    // for getting input from input.txt
    freopen("input.txt","r",stdin);
    //for getting error from error.txt
    freopen("error.txt", "w", stderr);
    // for writing output to output.txt
    freopen("output.txt","w",stdout);
    #endif
    BOOST
    int T=1;  cin>>T;
    while(T--) solve();
    cerr<<"Time taken : "<<(float)clock()/CLOCKS_PER_SEC<<" secs"<<"\n";
    cerr<<"My CLOCKS_PER_SEC= "<<CLOCKS_PER_SEC<<"\n";
    return 0;
}

91803529

//dsfdsfdsfdfdfvdfdvdgdvgdfgvdfgvdfxvd*gdfgdfgdfgvdfg
//dsgfdsfdsfgdsfgdgdsgdgfvdg
#include<bits/stdc++.h>
using namespace std;
#define ll long long 
#define rep(i,a,b) for(ll i=a; i<b; ++i)
void solve()
{
    //fsdfsdfdsfdsfdsfsdfsd
    ll a,b,sum=0; cin>>a>>b;
    ll x=abs(a-b);
    for(ll i=10; i>=1; --i)
    {
        if(i<=x) 
        {
            sum+=(x/i);
            x-=((x/i)*i);
        }
    }cout<<sum<<"\n";
}
int main()
{
    int T=1;  cin>>T;
    if(T==1) cout<<"fuck\n";
    while(T--) solve();
    return 0;
}

91859832
Same situation at B and C

Imagine coding the shit out of myself with digit dp just to realize that people get AC'd with simple greedy

Is there a greedy approach that works for F? I spent a bunch of time on a few ideas but couldn't get them to work.

Will an unsuccessful hacking attempt increase my time penalty in this round? I tried 2 hacks both were unsuccessful.

I like the contests by vovuh because the statements are clear and precise :)

Anyone else solved E by binary search?

are these cheaters phamquan-cbg and papaya.ahaha?: 91808904 91812659

I found these two VERY similar submission (when I was looking for people from my country to hack): + same strange input and output file name + exactly same loop

If you cheaters read this, please stop this immediately !!!

My screencast + live commentary, enjoy watching :)

https://youtu.be/nloGFTpdTJo

Can anyone tell the idea how to solve E efficiently if we have $$$k$$$ platforms?

Guys, could anybody help me understand whats wrong with my code for problem D? It gives the correct answer for all test cases in my machine, but it does not work at the Codeforces' server.

I'm sure the logic is correct, but don't know what happened. And unfortunately it was a valid submission in contest time.

MikeMirzayanov 91865709

https://codeforces.me/contest/1409/submission/91865709

https://codeforces.me/profile/enigma_13 Looking at this user, all his submissions have been hacked, because each of his codes has statements like if(t==xx). Although I think this way of raising ratings is very witty, should it really be encouraged?

Nice contest, thanks. Got stuck on C until late in the game when I discovered the constraints were easy, then ran out of time. See you next contest.

this type of hack should be banned right ?
91859832
91860660
91861276
91817628
91879637
91879985
91880404
91880766

Such a nice round it was! It deserve more upvotes...

nice contest

How can we solve E using DP?

System testing is in quarantine.

Why the ratings has not been updated yet..?

Why is rating change taking time?

why is this solution giving time limit exceeded?...i just ran it now...it got accepted

include <bits/stdc++.h>

using namespace std;

define endl "\n"

int main() { ios_base::sync_with_stdio(false); cin.tie(NULL);cout.tie(NULL);

int t; cin>>t; while(t--) { long long int n,x,y,i,j,num1=0,num2=0,mn=INT_MAX; vector v; cin>>n>>x>>y;

if(n==2)
     cout<<x<<" "<<y<<endl;

   else
   {
       for(i=1;i<=x;++i)
       {
           for(j=1;j<=10000;++j)
           {
               if(i+(n-1)*j>=y)
               {
                   if((x-i)%j==0 && (y-i)%j==0)
                      {
                          if(mn>(i+(n-1)*j))
                           {
                               mn=(i+(n-1)*j);
                               num1=i;
                               num2=j;
                           }

                           if(mn==y)
                              break;
                      }
               }

           }
           if(mn==y)
                   break;
       }

       cout<<num1<<" ";
       n--;
       while(n--)
       {
           num1+=num2;
           cout<<num1<<" ";
       }

       cout<<endl;
   }

}

return 0;

}

waiting for rating change.. solved 5 of 6 problems

is it rated?

this code is giving wrong ans.can someone please help me to find the bug.? this code is for question 3rd.

include<bits/stdc++.h>

using namespace std;

define ll long long int

int main() { int t ; cin >> t; while(t--) { ll n,x,y,i,j,dif=0,ans=0,i1=n,j1=n,k; cin>>n>>x>>y; vector<ll,ll>v1; // ll long long int ans=y-x; dif=ans; if(n==2){ cout<<x<<" "<<y; } else{ for(i=n-1;i>1;i--){ if(ans%i==0){ dif=ans/i; break; } } // cout<<dif<<" "; v1.pb(x); for(i=1;i<n;i++){ if(x+i*dif<=y){ v1.pb(x+i*dif); } else{ i1=i-1; break; } } // cout<<i1<<" "; for(j=1;j<n-i1;j++){ if(x-j*dif>0){ v1.pb(x-j*dif); } else{ j1=j-1; break; } } // cout<<j1<<" "; for(k=1;k<n-i1-j1;k++){ v1.pb(x+(i-1+k)*dif); } ll r=v1.size(); for(i=0;i<r;i++) cout<<v1[i]<<" "; } cout<<endl; }
return 0; }

My Java solution for E is just like everyone else's and the provided tutorial O(N Log N) and yet it keeps getting a TLE on test 5. Can someone have a quick look?

https://codeforces.me/contest/1409/submission/91970662

I've used FastIO, tried Java 8 and 11, nothing worked so far.

EDIT: I added some conditions to narrow down the problem, turns out Arrays.sort(A) is taking too long, which is very weird. Not sure if I'm doing something obviously wrong. Solution

EDIT 2: Turns out, randomly shuffling the array before sorting it worked!! Why would the unshuffled array take WAY longer?!

93053565 To solve problem F, I use an dp algorithm which has O(n^4) time complexity. It spend 1996ms, when this problem limits 2000ms. Lucky.