vovuh and div 3 still a better love story than Twilight :P

:)

All the best everyone :)

I wish this round becomes unrated for me soon.

And finally the wait is over!

DIV 3 rounds can be risky for higher specialists.

Again same question, Why don't we have some extra testers in these rounds(Educational/Div-3)? If I am correct this won't reduce the quality of contest, rather it would increase the contest's quality.

Can we please start having some more testers in Educational/Div-3 rounds? As they are rated contests and any issue noticed during contest would just affect participants.

Exicted for the rare div 3 round. Does div 4 round even happens? Hoping to see some nice questions

More than half of the comments are downvoted ! :-{

Is there a way to participate after the 9:35 UTC-5? Sadly, these competitions always happen during my school hours and I really want to participate. :(

Does anyone know that whether Technocup Elimination Round will be rated or not

yay DIV 3 round

Is this Rated for me? guys?

Can't wait to see the problems! Good luck everyone! :D

Wish you all the best ♥

Is it rated?

When will div. 4 return ?

Good Luck for Everyone :)

It's valuable for waiting such long time :)

Finally wait is over. Hope I can get rating above 1000 today:)

.

Hope I can reach green this time

What is the points distribution for the problems? Or are there none for Div. 3 contests.

int rating=1134;
rating+=150;

This comment section is shit.

If I submit multiple Accepted solutions, which one will be taken as my final solution (that is, used for others to hack?)

I felt like the dumbest person on the planet on reading this line after wasting 40 mins to solve a #P-complete problem.

What's the solution of E? Really liked problemsetting (especially F).

How to solve E ? F was easier than E for me

This contest made me remember the ABC from the past when first four problems are dead easy and last two are not touchable xD

Nice contest! I just want to ask what's the trick behind F. I've tried doing it using two pointers + segment tree, but that fails the test 2. My idea may be too off the right track, but that's what it is. Thanks.

EDIT: Now I see instead of 2 pointers I could have used binary search to solve, better luck next time I guess.

Guys what does it mean that there is a penalty of 10 mins for each wrong submission???

My Explanations for ABCD

A

Here given a positive integer n > 1 we want to print a permutation of distinct integers from 1 to n such that ith integer is not equal to i Consider the permutation {1,2,3 .. n} if we shift each element from 2 to n one position left and then print 1, that is {2,3,4 ...,n,1} then we are done Since here we are print the next integer for the positions 1 to n-1 and 1 at position n (n != 1),this is one of the required permutations.

Topic : Constructive Algorithm

B

Here we are given an array of n integers. We need to print the index of an integer which is unique and minimum among all possible such integers. So we maintain a map to track the frequency of each element. Iterate the map, check if frequency is one or not , if it is one then minimize the answer. if there is no unique element then print -1.

Topic : Implementation, Brute Force

C

Here we are given an array of positive integers We need to choose an element from this array of integers and use that integer to perform operations The operation is as follows: If we choose x , then remove any subbarray not containing x

We need to report the minimum number of operations So we can brute force all the distinct integers in the array and report the minimum answer

To do this , we maintain a map from integers to vector of integers. This map is from each unique integer in the array to it's indices .

For example let say the array as given in the sample case is [1, 2, 3, 1, 2, 3, 1] then our map will be [{1,[0,3,5]} , {2,[1,4]}, {3,[2,5]}]

To get the minimum number of operations for any given integer x (Let say), we remove all the indices which are not equal to x This can be done by doing the operation when the difference b/w consecutive indices of x is more than 1

For example take [1, 1, 66, 1, 77,88 , 1, 1] with x = 1, Now we have the indices of 1 as [0 ,1 ,3 ,6 ,7 ]

So we check we do the operation when consecutive indices have difference of more than 1. Here it is operation 1 — 1 and 3 (we remove 66) operation 2 — 3 and 5 (we remove 77,88)

Similarly do the operation for all unique integers and report the minimum ans

Topic : Implementation, Brute Force

D

We are given an integer n We need to print a sequence of maximum length such that it's product is n and for each element the next element(if exists) is divisible by the current element First we factorize the given integer n and obtain a map from prime factor to it's power. now we need to print the desired sequence. Since we need to print a sequence of maximum length, we sort the prime factors by their powers, so that we greedily have the element which occurs maximum times first. Let say we have 360,so we make a vector of pairs and sort it by power. that is

{2,3} {3,2} {5,1}

Now we iterate the vector of pairs, until the powers are >= 1

We insert the element until the remaining number is divisible by the current element going to be inserted

For example

we have 2 , remaining is 360/2 = 180, so we insert it. ans is {2}

we have 2, remaining is 180/2 = 90 , so we insert it . ans is {2,2}

we have 2 remaining is 90/2 = 45 , but 45 is not divisible by 2 , so we can't insert 2 , hence we insert 90.

This algorithm produces the maximum sequence since we are greedy picking the prime factor with maximum power.

Topic : Greedy, Implementation, Sorting

Will the formula for $$$E$$$ be: $$$n(n-1)-(n-no \,of\, vertices\, in \,the \,cycle)$$$

What is the case 7 on the problem D?

How to solve problem F? Well I applied two pointer approach so it was bound to get TLE. So, I guess it would include some binary search solution.

What was your approach?

Where can I get the editorial for this contest? I am new to codeforces. Any help would be apprecited.

easy peasy Japanesey

https://www.youtube.com/watch?v=7WfLE_IIDqA&t=2809s&ab_channel=AoxiangCui this Youtuber live-streamed the live contest today that's the reason there are so many submissions for problem D also.

please correct me if I am wrong as I saw the video a just after the contest and it had 83 views on it

where is the wrong in this code ???

"" wrong answer 161st numbers differ — expected: '2', found: '1' "" can I know it?

http://codeforces.net/contest/1454/submission/99493118

where is the wrong in this code ?

"" wrong answer 161st numbers differ — expected: '2', found: '1' ""

can I know it?

http://codeforces.net/contest/1454/submission/99493118

where is the wrong in this code?

wrong answer 161st numbers differ — expected: '2', found: '1'

can I know it?

http://codeforces.net/contest/1454/submission/99493118

Is there anybody who solved problem D with backtracking? :)

The problems were awesome!! The magic of Data Structure! ;)

submission: 99493024

if(n==100000123) {
    cout<<1<<endl<<2<<endl;
    continue;
}

submission: 99494601

if(n==2001) {
    cout<<10000<<endl;
    continue;
}

Make system tests more and useless. Why do this?

Today contest good contest. I very very like today contest. Make tomorrow contest. I give tomorrow contest.

E was an awesome problem!

Getting F a couple of minutes after the round's end :(

Nice set of problems

.

Now there won't be any div 4 rounds ??

Does E,F problems are actually meant to solved by div. 3 users ? Really, I saw some red coders took 30 minutes to solve E.

So how could they expect a div. 3 Candidate to solve problems like E,F in an hour ?

I solved problems B and C without realizing that a_i <= n, and I was very wasteful in general.
I was still very far from the time limit (It would be cool if someone would hack me :P).

I implemented B using a map and a set and even also sort, and I implemented C using a map.

Were those constraints meant to make implementation easier?

I did D in a weird way.
Checked every divisor's (except 1) highest power that divides n. Among them took the one with maximum power then generated the answer from that.
Submission: 99476498

Thanks vovuh for a round with such elegant problems. Nice learning. Very balanced set of problems which were very carefully crafted and well organized. I am sure this took a lot of efforts from you and team! Can't even emphasize enough on how much of these efforts from you guys help others like me, to enjoy and learn from CF competitions.

Appreciate your efforts!! Thanks again!!

Very nice contest with interesting problems. Much thanks to vovuh and MikeMirzayanov !!!

handle -> just_try_to_solve has coppied my solutions, as I was using ideone, My all solutions are skipped what should i do, even this person agrees that he copied, then why my solutions are skipped, Please tell something, that person who copied my solution is saying that he agrees that he copies

please put him out of contest, not me

my submission links are as follows — 1. https://codeforces.net/contest/1454/submission/99406543 2. https://codeforces.net/contest/1454/submission/99419833 3. https://codeforces.net/contest/1454/submission/99456510 4. https://codeforces.net/contest/1454/submission/99468339

hello,I want to know whether the result are published for this round. because i am not seeing any up and down in my rating also a message is comming "Your rating are rolled back and will be back soon".pls help during the contest i did a misktake which is after submitting the code for first problem which passes all the pretest i submitted it again with the code of problem B and it gives a compilation error then i correctly submit the code of problem A as well as problem B.pls help me

Last div.3 was rated for <=1600. But how it is rated for This id ? Before participating his rating was 1601.

Your method to find the size of the tree hung on cycle vertices was brilliant!