Finally another Div.1+2 after 3 months....

Hope to become Specialist again!

Hope to get everything back I lost in past few contests...

I hope to become an expert

Finally a Jordanian round by the goat himself

as a tester

Hopefully I can reach specialist this contest

Just one word, it is called “bestcpintheworld”

As a tester, can I participate then?

As a tester, I am un employed

thx for honorable mention means a lot

As a tester, problems are hot, but author is even hotter

Finally, my testing skills have been acknowledged

My first Div.1+2 after reaching 2100 let's GOOOOOOOOOOOOOOOOO

Yeah, I am definitely getting cooked.

as a tester, i wish i could get an honorable mention too.

Usually I do badly in long rounds hope I can redeem myself

As a tester who could not resist the temptation to open the problems, I hope you all enjoy them as much as I did.

I am afraid of giving those contest when there is prize in it, because there is more cheating in those contest.

Sorry I am new, is this going to be rated?

As a tester, employed is the GOAT

By looking at the score of the problems, HOLLLYYYY, WE ARE COOKED

H2 has less score than H1? how does that work?:-)

As a participant I encourage the arab writers problems ,testers, judges for hard perseverance , I want to say good luck for participants and I hope for us lucky contest

As Misaka16172, hope I become CM

Good luck to everyone participating in this contest! I wish you all the best and a fair contest.

Why is the score for H2 lower than H1?

Hope to become Specialist again!

As a "مقصّر" tester, I'm glad I didn't make it to the honorable mentions.

contest after a long bit ;pls no back to noobie

as an un employed person hopefully I'll be employed after this round

no way dominater reviewed this round lol

Hope I can become a newbie

After months of total zero practice im so happy that i solved the first two problems only. Even that im in beauty university still can knockout some people.

I don't deserve this h2 lol

Problem $$$D$$$ is so easy to think of the solution but real hard to implement it cleanly. Otherwise a relatively easy problem.

$$$C$$$ on the other hand gave me nightmares.

Problem F is excellent, I like it!

Idk why I participate in these combined div 1 + div 2 rounds for 3 hrs. I will never be good enough to perform well in these. Only outcome is -70 delta everytime fml

Enjoyed the problems alot, very good contest

C is gangster!!!

Solution sketches for A-D (I didn't get cooked):

A. If $$$a+1 \lt b$$$ print $$$-1$$$ otherwise print $$$a$$$ if $$$a$$$ and $$$b$$$ have the same parity otherwise $$$a+1$$$

B. Consider the frequency array $$$c$$$ of $$$a$$$, if there is a prefix of length $$$x$$$ in $$$c$$$ where the first $$$x-1$$$ elements of it are greater than or equal to $$$2k$$$ and the last is equal to $$$2k-1$$$ print YES otherwise print NO

C. Let $$$x = \operatorname{msb}(n)$$$, $$$k = 2^{x+1}-1$$$, then print $$$\lfloor 2^{\operatorname{lsb}(i)-1} \rfloor$$$ for $$$1 \leq i \leq k$$$

D. The slope of $$$f(x)$$$ changes at the key points $$$l-m+1$$$, $$$r-m+2$$$, $$$l+1$$$, and $$$r+2$$$ for each interval, so put all these points in a map and do some math to check if $$$k$$$ is between pairs of points

Enjoyed the contest

I managed to solve 3 problems, yay!

who say Ahh ?

Did H remind someone else of a certain problem in Looking for a Challenge? Now I regret not trying to understand its solution a bit more.

Also how to reconstruct the answer from the binary search in E?

When will ratings change ?

(Participating after 2 years)

While in early times I use to struggle with bits generally it appears in question B then I gave time read it patterns and I am able to answer it now it mostly appears at c and I cannot solve that after contest when I try toh find answers it always associate a new property of xor .,.....how to overcome it .......i already done 2-3 yt playlist and knows the basic

new color :yay:

Thank you for the contest!

I like how natural the problems are.

best cheater in codeforces get 3000+ rating idontwannadothisanymore cong. bro!

employed thank you for contest!

My Codeforces account chaitanya9999 has been disabled. I believe this may have happened due to a false positive or a misunderstanding, so I am respectfully writing to appeal the decision.

I want to state clearly that I did not cheat. I have never copied someone else’s code, shared my solutions during a contest, used another person’s account, or used any unauthorized help like AI. All submissions from my account were written by me.(only the template i use for some functions from past was written before as i use it in each submission and also i wont use it for now onwards). Also i was not able to solve C question , i solved A,B and D , D with difference array technique on my own.

If my account was flagged for suspicious activity or plagiarism, please manually review my submissions and account activity , and please enable my account as soon as possible.

Congratulations to the winners! Shortly you will be contacted via private messages with instructions to receive your prize.

As usual, we used the following two scripts for generating random winners, seed is the score of the winner.

import requests
import random
import string
import time
import hashlib

contests = [2271]

# [1, rank_start) get winners prizes
# [rank_start, rand_end] get random prizes
rank_start = 11
rank_end = 100

n_random_prizes = 10

def is_eligible(contest, party_name, rank, points, problems, last_submission_time):
    #return problems >= 1 and (not (party_name in new_accounts))
    return (rank <= rank_end)

def get_party_name(party):
    if 'teamName' in party:
        return party['teamName']
    else:
        return party['members'][0]['handle']

class Party:
    def __init__(self, contest, name, rank, points, last_submission_time):
        self.contest = contest
        self.name = name
        self.rank = rank
        self.points = points
        self.last_submission_time = last_submission_time

    def __lt__(self, other):
        if self.contest != other.contest:
            return self.contest < other.contest
        if self.rank != other.rank:
            return self.rank < other.rank
        if self.last_submission_time != other.last_submission_time:
            return self.last_submission_time < other.last_submission_time
        if self.name != other.name:
            return self.name < other.name
        return False

eligible = []

key = open('key', 'r').read()
secret = open('secret', 'r').read()
for contest in contests:
    rows_to_fetch = 35000
    rand = ''.join([random.choice(string.ascii_letters + string.digits) for n in range(6)])
    params = [f'contestId={contest}', f'from=1', f'count={rows_to_fetch}', f'showUnofficial=false', f'apiKey={key}', f'time={int(time.time())}']
    req_params = '&'.join(params)
    hash_params = '&'.join(sorted(params))
    h = hashlib.sha512(f'{rand}/contest.standings?{hash_params}#{secret}'.encode('utf-8'))
    sig = f'{rand}{h.hexdigest()}'
    req = f'https://codeforces.me/api/contest.standings?{req_params}&apiSig={sig}'
    r = requests.get(req)
    if r.status_code != 200 or r.json()['status'] != 'OK':
        print(req)
        print('Error: failed to fetch results of contest %d.' % contest)
        exit()
    results = r.json()['result']['rows']
    if len(results) == rows_to_fetch:
        print('Error: results are too long in contest %d, increase limit.' % contest)
        exit()
    for row in results:
        party_name = get_party_name(row['party'])
        rank = row['rank']
        points = row['points']
        problems = 0
        last_submission_time = 0
        for problem in row['problemResults']:
            if problem['points'] > 0:
                problems += 1
                last_submission_time = max(last_submission_time, problem['bestSubmissionTimeSeconds'])
        if is_eligible(contest, party_name, rank, points, problems, last_submission_time):
            eligible.append(Party(contest, party_name, rank, points, last_submission_time))

eligible = sorted(eligible)

for i in range(1, len(eligible)):
    if not eligible[i - 1] < eligible[i]:
        print('Error: unable to sort eligible at positions {} {}.'.format(i, i, i + 1))
        exit()

#print('Eligible for tshirts are:')
#for idx, party in enumerate(eligible):
#print('{} {} {} {} {}'.format(idx + 1, party.contest, party.rank, party.name, party.last_submission_time))


seed = eligible[0].points

print('Total %d eligible, seed is %d.' % (len(eligible), seed))


import subprocess
testlib_rand = subprocess.run(['./randgen', str(seed), str(len(eligible)), str(rank_start - 1),    str(n_random_prizes)], stdout=subprocess.PIPE)
winners = list(map(int, testlib_rand.stdout.split()))

print()
print('Winners are:')
for place in winners:
    print('{}'.format(eligible[place - 1].name))

#include "testlib.h"
#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
    if (argc < 4)
    {
        cout << "Command line arguments are: seed length prefix nwinners" << endl;
        return 1;
    }
    int seed = atoi(argv[1]);
    int len = atoi(argv[2]);
    int prefix = atoi(argv[3]);
    int nwinners = atoi(argv[4]);
    rnd.setSeed(seed);

    set<int> winners;
    while ((int)winners.size() < nwinners)
        winners.insert(rnd.next(prefix + 1, len));

    for (int i = 1; i <= prefix; ++i)
        winners.insert(i);

    for (auto winner: winners)
        cout << winner << " ";
    cout << endl;

    return 0;
}

nigger