hoping to get positive delta!!! (from a warrior race)

Hope this will be a great round :XD

ROAD TO EXPERT!!

Only two div. 3 people tested?

hope to reach $$${\color{green}{pupil}}$$$

$$${\color{cyan}{and}}$$$ $$${\color{orange}{good}}$$$ $$${\color{red}{luck}}$$$ $$${\color{purple}{everyone}}$$$ $$${\color{blue}{!!!}}$$$

P.S: not today :(

hoping to get positive delta!!! (Recover from last Div 2):)

Hoping to reach a specialist in this contest.

Hoping to solve 5 questions for the first time.

Score distribution?!?!?

i hope it goes well

Omg finally my first unrated div3

Hope to become div 3 unrated in this contest

hope to reach pupil

As a tester, I wish you all good results on this great round!

Hoping to reach pupil this time

good luck everyone

I just want 5 AC in this contest.

expect to expert

The internet in Iran is terrible due to the conditions I hope I don't have any problems posting.

When I tried to upload my solution to the 3rd problem I got a "Sorry, you have been blocked" message. I tried and it is now blocking sending in solutions for previous competitions too. I tried to find info on the "help" page, but nothing useful. Anyone know whom to write to, and/or why this would happen?

Contest with perfect level wise problem

Good contest, had fun!!

how to solve D

did anyone else do a randomized solution for $$$E$$$?

such a boring and uninspiring round. i felt like i was doing a codechef round smh. had the solution for F just couldn't be bothered to write it. i really dont know how any problems from C-F were accepted as actual problems, really disappointing

HOW TO SOLVE C?

Beautiful problem H!

Was it just me or was C more difficult than D and E...

nah top 100 div 3 in this contest, 70 cheaters, 30 smurfs

I think I won't be able to participate in the codeforces contest until further notice The internet speed here is terrible and it takes 5 minutes to get to any page (due to the war) Goodbye codeforces!

nah top 100 div 3 of this contest, 70 cheaters, 30 smurfs

Can E be solved without Dp If not can u explain the DP solution Much love yall

hope all AI-cheaters will get banned

Couldn't figure out why this fails on test2 in F: https://codeforces.me/contest/2121/submission/324900759

Is there a solution to E without dp ? If so please explain it If not can u explain the dp solution

Problem G : codechef

Had a lot of fun with problems F, G, and H. Thank you!

On a separate note, my solution to H was with lazy segment tree. Could somebody please tell me a cleaner idea? And, apart from that, my G uses three segment trees (well, four to be precise, but that was because I went crazy there for a sec), so a cleaner idea would also be appreciated.

I bricked problem F with sparse table and binary search... Turns out I don't have enough time sadly.

For problem F, can someone explain why am I getting TLE with this code though I used binary search?

// Author : Shailesh
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define vll vector<ll>
#define pb push_back
#define mp make_pair
#define endl "\n"
#define mod 1000000007
#define tot(a) a.begin(),a.end()
#define minii *min_element
#define maxii *max_element

// ------------------------------------------------------------------------------------



// ------------------------------------------------------------------------------------

void solve()
{
    ll n,s,x;
    cin>>n>>s>>x;
    ll a[n],i;
    vll pos;
    for(i=0;i<n;i++)
    {
        cin>>a[i];
        if(a[i]==x)pos.pb(i);
    }

    if(pos.size()==0)
    {
        cout<<0<<endl;
        return;
    }

    ll ind=0;
    ll pre[n];
    pre[0]=a[0];
    map<ll,vector<ll>>mp;
    mp[pre[0]].pb(0);
    for(i=1;i<n;i++)
    {
        pre[i]=pre[i-1]+a[i];
        mp[pre[i]].pb(i);
    }


    vector<ll> pge(n,-1); // prev greater element ind
    stack<ll> st;

    for (i = 0; i < n; ++i) {
        while (!st.empty() && a[st.top()] <= a[i]) {
            st.pop();
        }
        if (!st.empty()) {
            pge[i] = st.top();
        }
        st.push(i);
    }


    vector<ll> nge(n, -1);  // next greater element ind
    stack<ll> stt;

    for (i = n - 1; i >= 0; --i) {
        while (!stt.empty() && a[stt.top()] <= a[i]) {
            stt.pop();
        }
        if (!stt.empty()) {
            nge[i] = stt.top();
        }
        stt.push(i);
    }


    ll ans=0;
    for(i=0;i<n;i++)
    {
        ll start=pos[ind];
        if(pge[start]==-1 || pge[start]<i)
        {
            ll end;
            if(nge[start]==-1)end=n-1;
            else end=nge[start]-1;
            ll need=pre[i]+s-a[i];
            vll vec=mp[need];
            if(vec.size()!=0)
            {
                ll left=-1;
                ll l,r,mid;
                l=0;
                r=vec.size()-1;
                while(l<=r)
                {
                    mid=(l+r)/2;
                    if(vec[mid]<start)
                    {
                        l=mid+1;
                    }
                    else
                    {
                        left=mid;
                        r=mid-1;
                    }
                }

                ll right=-1;
                l=0;
                r=vec.size()-1;
                while(l<=r)
                {
                    mid=(l+r)/2;
                    if(vec[mid]>end)
                    {
                        r=mid-1;
                    }
                    else
                    {
                        right=mid;
                        l=mid+1;
                    }
                }
                if(left!=-1 && vec[left]<=end && right!=-1 && vec[right]>=start)
                {
                    ans+=(right-left+1);
                }
            }
        }

        if(pos[ind]==i)
        {
            ind++;
        }
        
            if(ind==pos.size())break;
    }
    cout<<ans<<endl;

}

// ------------------------------------------------------------------------------------

int main()
{
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    ll t;cin>>t;while(t--)
    solve();
    return 0;
}

why does this approach for F not work? what to change in this to make it work? Submission

Problem G was nice!!!

The first div 3 contest that went good : )

me solving F be like I need sparse matrix no wait there is no need.no wait I need it,ohh yeah it can be done without spare table

why the contest rating have not made any changes in already existing rating of mine? is the issue with someone else as well, it is not even showing in the graph as well

Some of these cooked me ~

Can anyone help me with C ?

Pretest case should be more strong enough for problem C.

Hi Folks,

This is my first contest ever and at the moment I am unrated. I solved 6 out of the 8 questions in this round. Can I expect some kind of rating after this?

Thanks

Such a nice contest it was in terms of the problems given. Hopefully, I also got what I aimed for.

hoping to get positive delta!!!

My pF got hacked (unordered map) QAO

here after long time , has cf changed something? i am not able to view other code for submissions.

I think the two hacks I made on C were test cases 9 and 10... and holy moly so many people got TLE on 10. I'll take it :)

when is the editorial coming?

voventa why no thanks to 74TrAkToR?

when will we get tutorials?

when will we get the tutorials?

Competitive Programming in 2025 – A Broken Race?

Two coders. Same leaderboard.

1. One writes 200+ lines, fails test case #83, debugs, and finally ACs.
2. The other pays ₹25 and submits instantly.

Result?

1. Both rank above you. One earned it.
2. The other bought it.

The problem: CP is turning into a “pay-to-win” model.

Impact:

1. Honest coders feel demotivated
2. Rankings lose meaning

The spirit of CP is at risk !!

The ask: Platforms like Codeforces, CodeChef, LeetCode must act fast. Cheating isn’t just breaking rules — it's breaking the community.

Let’s keep CP clean. Let’s keep it fair. Agree or disagree?

Простите за не доумение я сам в шоке что получились такие совпадение но Najibullo_prog это хейтер он создал аккаунт из моего имени не знаю что он что то решал но я сам в почти последних минут решал эту задачу думал эту будет не челевечно если мне даст большой минус и блок всех задач иза одних совподений а NAZIROV я сним знаком он решил задачу сам и бысрее чем я тоже решил после него. простите за недоумение я иза совподений вообще изменил стиль писание кода

Appeal for "My solution 324842333 for the problem 2121C significantly coincides with solutions of 1 Other", I was quite surprised and shocked seeing the mail, totally unexpected. I had submitted my code at 8:45 (IST) and then continued to code with my other problems and finishing the final one at about 10:07 (IST), All my solutions have a laid out consistent writing style, with significant inspiration from youtube tutorials and video lessons. I still can't figure out how my this other person, who submitted the problem about more than an hour later, got it same as mine, even though his solution looks like it's been directly off GPT. Please take a look at it and provide a solution. Thank you for your time and understanding.

Hello Codeforces Administration,
I am writing regarding the plagiarism flag on my submission 324828250 for problem 2121E, which was found to be similar to a submission by user Noodl3.

The reason for this similarity is that the problem is a standard application of "Digit Dynamic Programming". The solution follows a very rigid and well-known template that is publicly taught in numerous competitive programming tutorials and resources.
This standard template dictates the entire recursive structure, the state variables, and the transition logic. When two programmers independently apply this public template to the problem, the resulting code will naturally be almost identical in structure.

The similarity is a consequence of the problem having a single, standard solution path, not of any collaboration. I can assure you I have no connection to Noodl3 and wrote my solution entirely on my own.

I am happy to provide any further clarification needed to resolve this. I take the rules of fair play on Codeforces very seriously and thank you for investigating this matter.

324828250

D ,1709... I wanna what is the 1709 meaning;I am just interested in that