1778D - Flexible String Revisit

1265E - Beautiful Mirrors

MikeMirzayanov make the rollback happen asap please, i cant see cheaters enjoying their fake rating.

Please it has been over a month now since the last rollback.

Upvote if you agree.

Thanks! (please don't hate on mee)

Here are a few Expert level cheaters, who are gonna get the rollback and a ban probably.

inside_light

kindburnell7

kumardasaditya967

harsh_raj7

Vishwajeetkaran

redded

astm1

tsundere_

I hope they get banned soon.

It said my solution 288164892 is from telegram and Mike durov requested to skip me.

If I get banned/disabled I. hope everyone on codeforces remembers me as the most hated/ratisted person ever.

So many higher rated ppl have bullied me through toxic comments on my blog, mocking me for my IQ/skills/looks , I have one of the lowest contribution in the history of codeforces.

I hope people remember my sacrifice.

Thanks!

After 34 contests, tremendous amount of hardwork and passion, I finally reach Pupil while having 69 IQ only.

It took me nearly 6 months to do it.

Im so happy

Refact.ai Match 1 (Codeforces Round 985)

What type of contest is this ?

Can anyone explain it to me please ? Thanks!

How to solve problems that require ad hoc, I have very low iq.

I can not think of something on my own, i need ideas, i can only work with problems that have a direct one step solution.

how can i improve

Thanks

Here I'm admitting my mistake and taking the responsibility.

I did not know about the consequences of it, I did not really want to cheat. I was just checking if the codes would work or not that is why I submitted codes for problem C, E and F from telegram in the last Div.3 contest I gave.

I hope everyone will forgive me and I will not lose any rating.

Thanks you, I will never do this again.

We all know, any permutation is made up of disjoint set of cyclic swaps. Read more about it here

i.e to make the permutation sorted, we need to do k-1 swaps for each k sized cycle.

Total swaps => n — number of cycles.

A variation of this standard problem was asked in the recent Div.3 2033E - Sakurako, Kosuke, and the Permutation,

We have to make the permutation such that either p[i] = i OR p[p[i]] = i ,

interestingly, solution to this comes as k/2-1 for each k sized cycle.

Now it makes me wonder what if we introduce one more condition to it =>

either p[i] = i OR p[p[i]] = i OR p[p[p[i]] = i

What would the answer be ? my intuition tells me it should be something in the order of k/6 for a cycle k.

Can you guys help me with this ?

Also what would be the general answer if we have m conditions like this,

either p[i] = i OR .... .... .... OR p[p[p[p[p[...i]....] = i .

Any help would be appreciated, Thanks!

Please help me fill this list on how to improve to 1000 rating.

Things I know :

Input/output

Variables and loops

Array

Vectors

Maps

Sets

Functions

String

Pointers

GCD/LCM

Please let me know what topics should I cover

Whenever I see math problems, I give up because my math background is weak. I am a biology student, but I love doing cp as a hobby.

Can anyone help me what theorems and algorithms do I need to prove to become better and reach 1000 rating ?

Thanks for help

binary search, bezout theorem, riemann hypothesis ? is that enough ?

please dont troll

Hyper Log Log — link to wikipedia

I heard this is an important algorithm to learn to get to 1000 rating, Could anyone break it down in simple terms, or maybe share an analogy? Like, something a 900 rated would understand?

Q. What exactly is it doing? I mean, how does it "estimate" things instead of just counting them for real?

Q. Why does it use these "hash functions"? (Is it for randomness? Or...?)

Q. What is this "log-log" part in its name supposed to mean? Is there a double logarithm somewhere?

Q. How accurate is it, really? And how does it balance between accuracy and memory usage?

Thanks in advance, and sorry if my questions are noobish.

I got 6k rank just by solving problem A yesterday, how is it possible ?

I used to get 15k ranks by solving A,B sometimes and now it's 6k ?

Are cheaters actually dead ? I got +100 delta for the first time, I hope to reach 1000 rating soon.

Thanks!

Can anyone help me understand it?

I've had nightmares solving problems on this, can anyone tell me resources to study this?

Also is it really this important to learn to get to pupil ?

Thanks

Problem: Given an input string s and a pattern p, implement regular expression matching with support for '.' and '*' where:

'.' Matches any single character.​​​​

'*' Matches zero or more of the preceding element.

The matching should cover the entire input string (not partial).

Can anyone help me with this ?

i tried two pointers and it failed, then I looked at the solution. It was DP but I could not get the idea on how to think and understand that, Can anyone explain in easiest words to me please ?

Thanks

gholyo attractors 1.618034 123gjweq2

Given two numbers represented as strings a and b, compute their product and output product as a string.

|a| <=1e6, |b|<=1e6

How do I solve it, I brute forced it and it gives me TLE.

can anyone help me? is there an optimal way ??

My rating is 842, My lifetime goal is to get to pupil before I die.

4000 is something I can not even imagine, If I ever see someone with 4000 rating, i will ascend to the heavens immediately.

Thanks for reading my pain.

EDIT: My rating is now 743 after the contest (-99), seems like I will never reach pupil.

Its showing -84, but it was a testing round so shouldnt it be unrated for everyone ?

I dont want to lose my precious rating, Please help is this a bug ?

How to unfriend the user who was my friend earlier and now is disabled.

I dont wanna see such people in my friend list, How can I remove them.

Thanks for any help, greatly appreciated.

UPD: stop upvoting my blog, just answer my query MikeMirzayanov

UPD: Thanks to golden_ratio/1.618034 tourist_fantasy for helping me stop the haunting.

We generate permutation of given array randomly until we get it sorted.

It's expected complexity should be factorial n for n sized array, but I saw on google it's factorial n+1.

Can anyone explain to me how is it factorial n+1, because for a binomial distribution E(x) = 1/p(x).

Please purify my understanding.

Also is there any sorting algorithm better than bogosort ?

I joined codeforces on 16th May and it's 16th August today, It has been 3 months and I have no progress. I am still 3 digit rated. After giving every contest I am still not improving.

Is it really not for me ? Am I really 69 IQ ?

I bet no one in this world would get as little progress as mine if they practiced this hard.

Also the number of cheaters have risen significantly, impacting newbies like me.

Even after rollback I got no positive delta, It's disheartening.

With that I believe I will have to quit codeforces forever.

Goodbye, may'24 — august'24 cp journey

I checked submissions of the cheaters I caught and seeing them all 100% skipped made me very happy.

They get what they deserve.

Waiting for the rollback.

Good work MikeMirzayanov

nginx forbidden 403

Why do I get this alot nowadays when I open codeforces.com in my laptop ?

When I open it on my PC I don't get it.

What is wrong ? does anyone has any clue ?

Rating changes for last rounds are temporarily rolled back. They will be returned soon.

Why did they takeaway those rating points ? Can anyone explain to me ? What did I do wrong and why did they took my rating points to do some investigation upon me ?

2004E - Not a Nim Problem

int g[N];
int val = 1;
int vis[N];
void cal(){
    for(int i=3;i<N;i+=2){
        if(!vis[i]){
            vis[i] = 1;
            g[i] = ++val;
            for(ll j = 1LL*i*i;j<N;j+=i){
                if(i%2&&!vis[j]) {
                    g[j] = val; vis[j]=1;
                }
            }
        }
    }
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int t; cin>>t;
    g[1] = 1;
    cal();
    while(t--){
        int n; cin>>n;
        vector<int>v(n);
        for(int i=0;i<n;i++) cin>>v[i];
        int res = 0;
        for(int i=0;i<n;i++) res^=g[v[i]];
        if(res) cout<<"Alice"<<'\n';
        else cout<<"Bob"<<'\n';
    }
}

Whats wrong, its giving WA on testcase 3, 140th value differs found BOB correct Alice.

I'm struggling for 10 hours with this

UPD: haha what a funny bug. Thanks to WhisperingWillow