I just wanna make sure that I'm not a 100% sure already but I've a strong suspicion. You people can look at my suspicions below.

Its about ItsTimeToCookSundarSTEM. Bro took an institute's name which is quiet frankly the best CP institute here in Pakistan. (All 4 IOI members have been from there in both years of our participation with 6 medals)

Bro became a CM in 10 contests which is in itself quite shocking given the CP culture and awareness here in Pakistan.

You can probably see how shocking his contest history is already. His first contest was an adhoc heavy contest. The Gellyfish one and he failed there badly. I guess, we all know that GPT sucks on problems of those sort. Even there, if you go look at his submissions for A. Well, first look at the order. He submitted A for some times and then tried B, then got accepted on A. All that in 35 minutes from the beginning of the contest. The shocking part is that either he grinded hard after this contest to get so good (which he didn't) or he should be good enough already (which also doesn't seem like so). Even when you look at his submissions of A, just look at the difference in style:

Wrong Answer Submission for A

Accepted Submission for A

The next contest was a d3 where he failed again (LOL). Look at his submission for E. While writing a BLOG, I found something even funnier. Look at G from the same contest (Link). Bro all of a sudden threw using namespace std; away. bro threw #include <bits/stdc++.h> away.

And then, bro gets f**ed in the next d2 again because B and C were again observation heavy/adhoc... only managed to solve A. this looks pretty horrible already for someone who is newbie at this moment of time and will be an expert in just 2 more contests.

The next d3? Bro became a GM out of nowhere. Almost ak-ed the contest. Now with that almost you might be thinking he didn't solve the last problem? Well, he couldn't solve a fucking Div. 3 D. Yes, someone who got 37th rank in a Div. 3 couldn't solve a Div. 3 D!!!!

Even his solving order there is suspicious, its ACEFG-H(TLE)-B-D(WA)-H

The next contest in our series is an Edu. There he managed to solve 4 problems. You might be thinking ABCD given how amazing Edu Rnd 180 D was but he didn't solve that. He solved E and not D FFSSSS!!!

He also took 29 minutes to solve A. (Maybe trynna make it less obvious or idk what)

The next contest is again a d3, the contest where he finally becomes an Expert. In this contest, he took 2 minutes to solve E after solving D. and then in the next 19 minutes bro got a WA1 on F (which was a constructive) and solved G toooo! and guess what, he couldn't solve F because GPT can't do constructives or some sht!

Also wtf is this solving order? BADE-F(WA1)-G-C-F(WA1)

The next d2 doesn't have much highlights in our series but it was one amazing plot twist. Bro is about to become a CM in the next contest but he used Dijkstra in A when it was a two-liner 😭

The next d2 was again a quit GPT-able contest and bro became a GM all over again with his weird solving orders all over the place. He did ADC-E1(WA1)-E1-B and then some wrong submissions for E2 and F which were too hard for GPT.

The next contest is my favourite actually. It was the second last d1/2 where d2E has three subtasks. the RBS interactive one. Bro was giving the d1 and bro couldn't solve any of the subtasks for C 😭😭 . (Maybe bro should upgrade his ChatGPT version and then give it a try on interactives?)

and then the final 10th contest. It was the last d1+2 (the Atto round). Everybody knows that H was solvable with GPT and guess what! He did exactly that!!! Even here, he took 22 minutes to solve A and then right in the next two minutes he got an AC on C. I believe GPT failed on B because it again, was an adhoc... and then he did some wrong submissions and after more than an hour got an AC on H directly. Yes, bro didn't do B or D and got an AC on H 😭😭 and then all of a sudden switched to Python for solving D. idk why, it wasn't anything special. And then solved B in the end. Even there, he had this weird ahh thing which he didn't have in any of the submissions before this.

    if (fopen("B.INP", "r")) {
        freopen("B.INP", "r", stdin);
        freopen("B.OUT", "w", stdout);
    }

Now you can judge. I request MikeMirzayanov, Vladosiya, KAN and other admins to look after this. He's ruining the reputation of a country with his dirty things. and If for some reason he is legit, then I'll write an actual apology too but he will have to publicly prove it here.

IOI 2025 is just around the corner. This year it'll be held in Sucre, Bolivia. Discuss things here including predictions, links for live scoreboards/streams, and solution for the tasks too maybe after they come out.

Here is the schedule for the main contest:

• Contest Day 1 — Wednesday, 30th July, 10:00-15:00 GMT-4

• Contest Day 2 — Friday, 1st August, 10:00-15:00 GMT-4

• Closing Ceremony — Saturday, 2nd August, 16:30-19:30 GMT-4

Below are some important links:

IOI 2025 Website

Schedule

Errichto's Live Stream Day 1

Practice session problems

Leaderboard Day 1

Errichto's Live Stream Day 2

Congratulations to the Top 3

1. BreakPlay

2. Mingyu331

3. umbrella-leaf

today, on several occasions problems were loading as a PDF file instead of the usual page. It was happening in the morning, then it disappeared and now it happened again but only once. Is it some bug?

Edit: It's been so long and nothing's fixed. This is too frustrating. You open a problem from problemset, you solve. then go to problemset submit then check the problem index (problem number), write it. you get accepted and then to check editorial solution you click on problemset link and it takes you to pdf again 😭 Now I'll have to search for that contest number which apparently isn't the same as the number in the link and then search for the contest in contest page. What is this? 😭😭😭

I'm writing this as a bug report because I don't know where else to report. I tried sending a message to atcoder_official but I couldn't.

Basically when I go to submit a problem, the language isn't selected as usual. Then I select the language, paste the code and click submit and then it says Error (nothing else). It also doesn't show CAPTCHA as it does usually when submitting out of practice. atcoder_official, please have a look into it. Below are some screenshots too.

Thank you!

I want to report some cheaters (i'm very sure they're cheaters). Suspect submissions will also be linked.

Ali-nuces

At first sight you may think that this person is actually legit. Last contest is ok? Second last contest is ok-ish? (in the sense that there are no comments in the code, coding style is unique). Well, apart from the fact that this intelligent person who got CM in 6 contests couldn't solve a D2B and used Java, C and then C++ to AC lol. 3rd last contest is also kinda fine apart from fact that this genius had to switch languages to get AC on C and D. (I wish I was this much multilingual 😭😭). in the 4th last contest (which was just the 3rd contest of this geniousity), he even switched to RUBY!!!. and here comes the main submission...

2072-E from this geniousity. Bro wrote an entire documentation while coding 🤣

Now, lets come to his D(link) from the same contest. (Take your seats to have a great laugh). who tf uses pointers and memory checks in competitive programming bruh 🤣🤣

        int* a = (int*)malloc(n * sizeof(int));
        if (a == NULL) {
            printf("Memory allocation failed\n");
            return 1;
        }

With this, i'm leaving the case of this person in the hands of Mike and the codeforces coordinators.

Darkman01

Bro has just entered and unfortunate for him that he got caught before even achieving a good color lol.

I don't think there can be anything more obvious that this

Bro even tried copy pasting blogs from gpt or somewhere and got hammered hard 🤣🤣 . Better luck next time diddy.

THE MAIN PERSON: Abdullah-Nuces

Bro is the definition of wikipedia. Thank you sir for having such good documentation in your submissions. It will surely help us poor people who are weak to understand the problem. We love you for that.

Anyways, this is the most serious case as he has 6th contest left which gives a +50 additional delta. Now if he manages to succeed in his shenanigians again and get a good +70-100, he will be rank 1 in Pakistan which will be a huge shame for us. So, before anything that much serious happens, I'd request MikeMirzayanov and other codeforces coordinators to please ban this guy. He's bringing disgrace to his country. We don't own stupid people like that.

Also if you're wondering why I didn't give any link to his submissions etc just go his previous contests you will see yourself. Bro is multilingual, he's a wikipedia trying to not make it too obvious but an absolute failure in it!

I hope MikeMirzayanov, KAN, Vladosiya and other coordinators whom I don't know please take action on these stupid people especially the last one.

If you know more people, feel free to tag them in the comments.

and btw, "ban Abdullah-Nuces" in the comments, everyone!

Codeforces Blitz Cup is going on and it looks pretty fun. I think it'd be nice to have it for everyone where we can have random 1v1s using matchmaking with people around the user's Codeforces rating. Maybe having a separate rating for Blitz would also make it more fun but matchmaking should be based on Codeforces rating. Problems should also be around the user's Codeforces rating which would make it more balanced and fun.

(Obviously, there's no need for streaming and commentary except for tournaments.)

Edit:

1. With a large amount of upvotes, I'd like to tag Sir MikeMirzayanov. Sir, please consider this 🙏🙏

2. Addressing the issue that What if someone cheats or we've seen the problem already?:

• In my personal opinion, fun is more important.
• If blitz rating system like one in chess.com is used then the cheaters will not affect the rating as well.
• If one of the user has seen/solved a problem already then maybe having a Cancel/Draw option will he useful if both of them are honest which would pretty much create an element of fairplay.

What do you all think?

...with this rate imma be LGM in no more than 201 contests...

congratulations for winning IOI 2024 zhoukangyang

A — Alternating Sum of Numbers

#include <bits/stdc++.h>

using namespace std;
#define int int64_t

int32_t main(){
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        int ans = 0;
        for(int i = 1; i <= n; i++){
            int x;
            cin >> x;
            if(i & 1) ans += x;
            else ans -= x;
        }
        cout << ans << "\n";
    }
}

B — Three Brothers

#include <bits/stdc++.h>

using namespace std;
#define int int64_t

int32_t main(){
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    int a, b;
    cin >> a >> b;
    cout << (a ^ b) << "\n";
}

C1 and C2 — Message Transmission Error(Hard Version)

#include <bits/stdc++.h>

using namespace std;
#define int int64_t

int getRandomNumber(int l, int r) {
    std::random_device rd;   // Seed generator
    std::mt19937 gen(rd());  // Standard mersenne_twister_engine seeded with rd()
    std::uniform_int_distribution<> dis(l, r);  // Distribution in range [l, r]
    return dis(gen);
}

struct Hash{
    int h1 = 0, h2 = 0;
    int m1 = 1e9+7, m2 = 1e9+9;
    int p;
    vector<int> pref1, pref2, power1, power2;

    Hash(int base): p(base) {}

    void build(string& a){
        power1.push_back(1);
        while(power1.size() < a.size()){
            power1.push_back((power1.back() * p) % m1);
        }
        power2.push_back(1);
        while(power2.size() < a.size()){
            power2.push_back((power2.back() * p) % m2);
        }
        pref1.resize(a.size() + 1, 0ll); pref2.resize(a.size() + 1, 0ll);
        int j = 0;
        for(int i = 0; i < a.size(); i++){
            h1 = (h1 * p % m1 + (a[i] - 'a' + 1)) % m1;
            pref1[i + 1] = h1;
            h2 = (h2 * p % m2 + (a[i] - 'a' + 1)) % m2;
            pref2[i + 1] = h2;
            j++;
        }
    }

    pair<int, int> getHash(int i, int j){
        int raw1 = pref1[j + 1] - ((pref1[i] * power1[j - i + 1]) % m1);
        int raw2 = pref2[j + 1] - ((pref2[i] * power2[j - i + 1]) % m2);
        return {(raw1 + m1) % m1, (raw2 + m2) % m2};
    }
};

int32_t main(){
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    string s;
    cin >> s;
    int n = s.size();
    int base = getRandomNumber(55, 1e8);
    Hash hash(base);
    hash.build(s);
    int ans = -1;
    for(int i = 0; i + 1 < n; i++){
        int len = max(n - i - 1, i + 1);
        if(len == i + 1) continue;
        pair<int, int> pref = hash.getHash(0, len - 1);
        pair<int, int> suff = hash.getHash(n - len, n - 1);
        if(pref.first == suff.first && pref.second == suff.second){
            ans = len - 1;
            break;
        }
    }
    if(ans == -1) cout << "NO" << "\n";
    else{
        cout << "YES" << "\n";
        for(int i = 0; i <= ans; i++) cout << s[i];
    }
}

Also if someone has solved C1 and C2 with KMP, please explain your solution.

As I said, here's the screencast for edu codeforces round 169. i'm fully committed to my previous apology blog

https://youtu.be/1uBUCeu6nvo

Here's the screencast for codeforces round 967(div. 2)

https://youtu.be/lnsVi4GOeNo

Hello codeforces,

In this blog, I wanna admit my cheating and bad behaviour in my competitive programming career on codeforces. With greed of rating and pressure of rating, I've cheated sometimes. My original account was Wasif_Shahzad. It got skipped some times(4-5 ig). I was really sorry about my behaviour and decided to abandon that account.

1. In the last AtCoder Beginner Contest, I used ChatGPT to solve problem B in which I got stuck on in implementation. I didn't know the rule change of atcoder. I'm really sorry to atcoder community for that. I promise that I will never use chat GPT in ABCs.

2. Also Recently, I've got some public accussations under the announcemet blog of recent div. 3 contest. I've read the whole thread now and came to know some people think I cheated cuz I got hacked on E. There was some discussion on errichto discord server and people were saying I cheated YET again in yesterday's contest. I felt very bad and decided to leave the server finally because some people were requesting the mods to ban me. Let me clarify what happened yesterday. I saw hacks and saw a submission which got hacked and had that SPECIAL CASE. I asked chat GPT to generate a case for me which would work. Then I wanted to check if that would work or no. so I submitted the code from my account and then hacked that submission myself. You can see the submission times and that I hacked it myself. Moreover, it doesn't make any sense to cheat after the contest is over.

3. I've decided that from now on, I'll record every contest and publish it on YouTube to be on safer side.

4. I request MikeMirzayanov to ban the account Wasif_Shahzad please. I promise I'll never be in anything like this again and lastly, I hope that the community will accept my apology.

UPDATE: I legit forgot to write about the d2 incident where I got FST. I'm really serious about my behaviour. I wouldn't have written this blog and exposed myself if I weren't being honest. I'm really really sorry again. The decision is of the community now.

Next year is my last chance for IOI and I wanna give my best to get there. I'm facing a few issues and want to ask for help.

1. I'm very bad at reasoning and proving basic mathematical problems/claims

I face a very hard time when facing mathematical problems regarding number theory and mathematics and their proofs. The only proof I know about is PROOF BY AC. other than that, I don't know anything but sometimes it isn't good. I think I need to develop it on mathematics side and if someone knows some sort of website like Codeforces where I can practice my proving skills a.k.a. basic practice for IMO please tell in comments. My goal is to NOT go to IMO but I think that would help a lot.

2. Need beginner friendly resource for OI practice where I can practice problems in ascending order of difficutly

My current practice rating on codeforces is 1600. I'm planning to solve the entire first page of problemset of 1600(in ascending order). I also wanna grind OI problems because they're quite different from cf problems. The only website I know is qoj.ac on which I find the problems very hard so I'd like if someone knows any website/cf group from where I can start from easy OI problems, please let me know in comments.

Additional info: for some reason I find USACO bronze very hard and I couldn't even solve a single problem in US Open so that's why I don't usually practice there.

I'm very serious about my dedication. Even though I have like 7-8 months for next year's IOI team selection, I'm ready to practice with full zeal and zest.

Thank you!

As we all know physical activities are super important along with competitive programming and other computer related things. What do you do then? I personally like to play cricket and football. Also I go for jogging with my friend on a racetrack everyday.