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On touristCodeforces Round #850, 1 minute ago
0

why my submission page is not loading? When I am opening the page it shows Your text to link here...

On touristCodeforces Round #850, 17 minutes ago
0

What dose "dp" stand for? I thought it cannot be "dynamic programming"

On touristCodeforces Round #850, 19 minutes ago
0

amazing round!

On touristCodeforces Round #850, 21 minute(s) ago
0

For This, I guess my logic is same but there is actually no need to harcode stuff, though It is something very tedious. Here is my code 192350442

Ps: On a seperate note who is she on your cf dp?

On touristCodeforces Round #850, 23 minutes ago
+1

Wow clean and smooth implementation

On touristCodeforces Round #850, 23 minutes ago
0

Excellent Contest,Thanks for Tourist Cooperation For this Wonderful contest And especially for the first 4 problems

On touristCodeforces Round #850, 32 minutes ago
+1

Tgod!!!i love you.This is my first time to reach the top 600.

On touristCodeforces Round #850, 34 minutes ago
0

See my comment Although it's not elegant, I think it's easy to understand.

On touristCodeforces Round #850, 36 minutes ago
0

It's graph problem

On touristCodeforces Round #850, 38 minutes ago
+1

Agreed.

On touristCodeforces Round #850, 41 minute(s) ago
+2

Guess I'm too Indian to understand this.

On touristCodeforces Round #850, 42 minutes ago
0

Thank you!

On touristCodeforces Round #850, 44 minutes ago
+3

However personally I think this may just be a coincidence and could not prove anything.

On touristCodeforces Round #850, 45 minutes ago
+2

the second testcase is 4 1 5 4 1 1 and rearranging it we get 1 1 4 5 1 4.

On touristCodeforces Round #850, 46 minutes ago
0

damn, nice to see you on cf wilo

On touristCodeforces Round #850, 47 minutes ago
0

1B's implementation is too horrible. I think there is no need to output the sequence of exchanges, it does no good but making this problem a lot more difficult to implement.

On touristCodeforces Round #850, 47 minutes ago
0

i am also facing some problems, sometimes it works sometimes it gives error

On touristCodeforces Round #850, 49 minutes ago
+19

Heh, Heh, Heh, aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

On touristCodeforces Round #850, 51 minute(s) ago
+3

well it's broken for me and i don't know why

On touristCodeforces Round #850, 51 minute(s) ago
0

The implementation may not be ugly if you organize your code well. Maybe you can refer to this code by jiangly. The code is neat and it only took him 10 minutes.

On touristCodeforces Round #850, 54 minutes ago
0

1D can be solved in dynamic programming and polynomial tricks in $$$O(n\times 2^n)$$$ time, but I've heard there exists other solutions which do not require polynomial or the modulo $$$998244353$$$.

On touristCodeforces Round #850, 54 minutes ago
0

my first div2. really good

On touristCodeforces Round #850, 55 minutes ago
0

How to solve the "Letter Exchange"?

On touristCodeforces Round #850, 55 minutes ago
0

In both the problems you only need to resolve the cycles of length 2 then cylces of length 3.

On touristCodeforces Round #850, 56 minutes ago
0

For cycle of length 2: If suppose $$$ith$$$ person needs $$$w$$$ and it has an extra $$$i$$$ and if the $$$jth$$$ person needs an $$$i$$$ and it has extra $$$w$$$, we can perform the swap and both will be satisfied in 1 operation. We can do this for all possible combinations of letters.

For cycle of length 3: If suppose $$$ith$$$ person needs $$$w$$$ and it has an extra $$$i$$$ and if the $$$jth$$$ person needs an $$$i$$$ and it has extra $$$n$$$, and if the $$$kth$$$ person needs $$$n$$$ and it has an extra $$$w$$$, we can first perform the swap between $$$ith$$$ and $$$jth$$$ person so now $$$ith$$$ person needs $$$n$$$ and it has an extra $$$i$$$, then we can perform the swap between $$$ith$$$ and $$$kth$$$ person. So all three will be satisfied in 2 operations.We can also do this for all possible combinations of letters.

On touristCodeforces Round #850, 57 minutes ago
0

So I'm really interested in how to solve 1B so fast.

On touristCodeforces Round #850, 57 minutes ago
0

well I spent about 1.5 hours on 1B and when I saw 1D I thought I should solve that problem in the first place instead of 1B. My solution to 1B is horrible and I rewrote my code twice, once because of my algorithm is incorrect and the other because I got sick of the rubbish code I had written.

On touristCodeforces Round #850, 58 minutes ago
+6

I liked the contest, thank you tourist for the problems!

On touristCodeforces Round #850, 59 minutes ago
0

In DIV2 C, the only observation is that we should perform the query of 2 as the last move, right?

**Proof : ** Let's suppose we make a "chain" of 1, 2, 3, .., x and we have some element remaining y(y > x + 1) then after the operation 2 we'll be left with only y — x and if we'll need y — x type 1 operations now but if had we made it x + 1 earlier then y — x — 1 type 1 operations would've been needed

lemme know if something seems wrong.

On touristCodeforces Round #850, 64 minutes ago
+3

I have the same question. Maybe tourist also surf foreign websites? (wwwww

On touristCodeforces Round #850, 64 minutes ago
0

I don't get it.

On touristCodeforces Round #850, 66 minutes ago
0

but there is a huge score difference, for example 750 points between D and C so it's kinda justified

On touristCodeforces Round #850, 67 minutes ago
0

omg tourist round!!!

On touristCodeforces Round #850, 69 minutes ago
0

If I understand correctly, all the people are nodes and an edge is connected between someone who needs and has excess of the same letter? In this case why can't the size of the cycle be more than 3?

On touristCodeforces Round #850, 71 minute(s) ago
0

how it is similar, can you please elaborate sir

On touristCodeforces Round #850, 74 minutes ago
0

Why i can't upsolve?

omg tourist round

On touristCodeforces Round #850, 78 minutes ago
+23

Is div1-A's sample2 made by tourist himself?? I'm astounded him using Japanese internet meme how did he know that??(I know that it's well-known in Chinese...)

On touristCodeforces Round #850, 79 minutes ago
0

Problem D writing a perfect code, to getting RE on test 19

Reason: I wrote an assert statement to debug the TLE cause in the local machine Locking the problem and realizing I can't change this

My AC code

On touristCodeforces Round #850, 80 minutes ago
0

I don't know if there exists some elegant solution (I've seen some simple-ish ideas by people but not full solutions), but I personally had to write (and copy-paste) over 200 lines of code (I believe there has to be something simpler) to cover all cases.

On touristCodeforces Round #850, 81 minute(s) ago
0
Idea
On touristCodeforces Round #850, 82 minutes ago
0

I tried using bit-masking (coding needs and excesses as bits, 64 possible states in total, the first 3 bits for needs of w, i, and n and the other 3 for excesses). The observation I made was that there can be only 2 kinds of moves, i-j and i-j-k.
My implementation however got the better of me considering there were 9 unique cases in total, the code could have easily exceeded 600 lines if I had continued, lol.
Could you share your approach?

On touristCodeforces Round #850, 83 minutes ago
0

Here is a problem with same idea as today's Div1B/Div2D in case anyone is interested.

Problem

On touristCodeforces Round #850, 84 minutes ago
+3
On touristCodeforces Round #850, 85 minutes ago
+1

I counted all combinations and greedily matched those that benefit both people
After that greedily matches those that benefit only one of them

On touristCodeforces Round #850, 86 minutes ago
0

Any hints / elegant approaches on solving div2-d?

On touristCodeforces Round #850, 86 minutes ago
+2

One of the most unbalanced rounds (Div. 2) in a while.

On touristCodeforces Round #850, 87 minutes ago
0

Div1E, not Div2E

On touristCodeforces Round #850, 87 minutes ago
0

Can you tell your approach? I thought this was similar to the question where we had to distribute equal number of ones among all rows, but just with 'w','i' and 'n'. But I had no idea how to implement it, if it even is correct in first place

On touristCodeforces Round #850, 90 minutes ago
+5

My solution of D is a very ugly implementation

On touristCodeforces Round #850, 90 minutes ago
0

You do a dp of size $$$n \times 2^n$$$, where $$$dp[i][j] = $$$ number of ways that the number $$$j$$$ leads (is the highest value) a group of size $$$2^i$$$, and will lose all matches after this. Solve this dp top down.

Here's a snippet of the solution

Code

couldn't get ac because coded too slow... :(

On touristCodeforces Round #850, 93 minutes ago
+11

Was div2D ugly implementation?? There was a huge gap no of solves for b and d. I have no idea how to even start approaching D

On touristCodeforces Round #850, 95 minutes ago
0

I've simulated this approach for some example cases. Maybe we should add an adge pointing from a "extra" char to a "lack" char, for example, "www"-->(w->i),(w->n), "iiw"-->(i->n), where (char1->char2) is an edge pointing from char1 to char2.

Then we would get a directed graph with nodes {w,i,n}, each node has equal in-degree and out-degree. We can regard a exchange as cancelling 2 edges with same nodes and different direction, like (w->i),(i->w) --> nothing; or merge a path of 2 edges into 1 edge, like (w->i),(i->n) --> (w->n). We need to store the index of people in edges. To achieve the minimun number of operations, we need to use as more the first operation as possible. Therefore, first we cancel every pair of (w->i),(i->w) until one of them runs out, similar for (i->n),(n->i) and (n->w),(w->n). Then if there're edges remained, by the property of in-degrees and out-degrees, they must form some cycles like (w->i),(i->n),(n->w), or reversely, (w->n),(n->i),(i->w), we need to do 2 operations for each cycle.

On touristCodeforces Round #850, 95 minutes ago
0

Mistaken, ignore.

On touristCodeforces Round #850, 96 minutes ago
0

why so worry about rating?

On touristCodeforces Round #850, 98 minutes ago
0

is this approach correct for B? align the first cake with the first dispenser, such that a1-w=b1-h, then for the rest of n-1 cakes check if you can move them to the left by less or equal to (a1+w)-(b1+h) so that they are aligned with their dispensers, if ever needed to move the cake to the right the answer is "no" otherwise "yes"

On touristCodeforces Round #850, 98 minutes ago
+3

Yes that's it

On touristCodeforces Round #850, 98 minutes ago
0

Though my problems were comparatively easier but still I was able to solve only 1

On touristCodeforces Round #850, 101 minute(s) ago
0

Can anyone explain to me how to solve problems E and F on Div2? Thank you so much.

On touristCodeforces Round #850, 102 minutes ago
0

Oh, didn't FST. So my rating won't drop too much.

On touristCodeforces Round #850, 103 minutes ago
0

Based on previous experience, will be after about 1 week.

On touristCodeforces Round #850, 103 minutes ago
0

what is FST?

On touristCodeforces Round #850, 106 minutes ago
0

How t solve 1D?

On touristCodeforces Round #850, 106 minutes ago
0

Cool round!))

On touristCodeforces Round #850, 109 minutes ago
+3

we are on the same boat

On touristCodeforces Round #850, 110 minutes ago
0

where editorial?

On touristCodeforces Round #850, 111 minutes ago
+3

"If there are multiple solutions, print any", this sentence was missing at the beginning in 1B, that was bad.

On touristCodeforces Round #850, 112 minutes ago
+24

If problem setter is tourist, We expect better Contest, but I can say, this is the worst contest, I have ever given. Respect to tourist but Worst Contest ever seen... Mainly Problem D

On touristCodeforces Round #850, 112 minutes ago
+6

C, D and F are interesting, E is quite standard, and B is too hard for me.

On touristCodeforces Round #850, 112 minutes ago
0

So when will system test begin?

On touristCodeforces Round #850, 113 minutes ago
+3

My username is pretty much how i felt during the entire 3 hrs.Last tourist round for me.

On touristCodeforces Round #850, 114 minutes ago
+1

Thanks :)

On touristCodeforces Round #850, 115 minutes ago
0

cf carrot extension

On touristCodeforces Round #850, 115 minutes ago
+1

Even after that you completed the contest withing 2 and half hours , really appreciating.

On touristCodeforces Round #850, 115 minutes ago
0

What programm do you use to see performance?

On touristCodeforces Round #850, 116 minutes ago
+17
My worst performance in a while T-T
On touristCodeforces Round #850, 117 minutes ago
0

YES ~ tourist probably

On touristCodeforces Round #850, 118 minutes ago
0

Same here, pretty much hardcoded everything only to get WA in the end for D

On touristCodeforces Round #850, 118 minutes ago
0

And a typo: not -> now

On touristCodeforces Round #850, 119 minutes ago
+5
1C
On touristCodeforces Round #850, 119 minutes ago
+9
Especially liked F
On touristCodeforces Round #850, 119 minutes ago
0

you don't really need to find x, but just need to get hold of a range ie. l,r such that l<=x<=r and then if l>r then output no otherwise yes

On touristCodeforces Round #850, 2 hours ago
0

Is this is a implementation problem?

On touristCodeforces Round #850, 2 hours ago
+5

I used a super ugly implementaion with upto 30 lines hardcoded data.

I don't want to solve problems like this again.

It seems that here's a pretty good solution with graph theory:

build a three-node graph. when it's 'wwi', link w to i, when it's 'www', link w to i and w to n. and so on.

Finnally match edges with same endpoints but different directions firstly. then cycles with length 3 remain.

On touristCodeforces Round #850, 2 hours ago
+1

The submissions are not public yet.

On touristCodeforces Round #850, 2 hours ago
0

Which browser are you using?

On touristCodeforces Round #850, 2 hours ago
+2

I just wrote the ugliest code of my life for problem D (B for div1): 192346636 Didn't really like this problem, and C was too easy, it should have been B. Other that these, I enjoyed the contest, although I would have loved to have time for E :(

On touristCodeforces Round #850, 2 hours ago
0

why I am not able to submit solutions, it says contest is over even though 80 mins are left? Is it so that you have to participate in initial rounds so as to participate in the Final Round? It does display System Check is Pending.

On touristCodeforces Round #850, 2 hours ago
0

Me too!!Got stuck and got 9 WAs :(

On touristCodeforces Round #850, 2 hours ago
+87

my suggestion after this,1782,1561: avoid vk cup rounds for boring implementation problems and random performance

On touristCodeforces Round #850, 2 hours ago
0

Which extension/website you use to get predictions? CF preictor extension is currently now working for me.

On touristCodeforces Round #850, 2 hours ago
0

Please give some hint how to solve problem 2D.

On touristCodeforces Round #850, 2 hours ago
+86

C was too hard for me ;)

On touristCodeforces Round #850, 2 hours ago
+10

Was Div1C a seg tree + binary search (based on the idea that after some time some numbers are fixed)? I could not come up with easier solution.

On touristCodeforces Round #850, 2 hours ago
+26

Why did you put a trivial 12D DP (= easy idea, looooong implementation) as Div1E? It's not funny.

On touristCodeforces Round #850, 2 hours ago
0

Wait till the System Testing gets over.

On touristCodeforces Round #850, 2 hours ago
+6

Really interesting div 1 contest, thanks!

On touristCodeforces Round #850, 2 hours ago
0

Does the problem 2D involves case work on bitmask? or this is graph problem?

On touristCodeforces Round #850, 2 hours ago
0

very hard problems

On touristCodeforces Round #850, 2 hours ago
+7

If my solution failed for a HIDDEN PRETEST, (like Pretest 2), how much time after the contest can i see that testcase? Because the contest has ended, but I cant see the testcase which went wrong.