when asking for downvotes and asking for upvotes are unsurprisingly in the same SCC

posting mind blowing meme to get upvotes :

As an author, me too.

omg that thumbs up emoji looks fabulous

also YOU SHOULDNT BRAINSTORM THE SOLUTIONS WITH OTHERS DURING CONTEST ITS AGAINST THE RULES

(yes, I couldn't believe my eyes after reading that line)

after the contest, I realized.

You (plural) might have tried your best to make the problems as interesting as possible, but you (singular) didn't! Shame on you!

F*ck you problem stoler.

Let's downvote him to make his contribution lower than zxyoi cuz it's the second time such situation happens

What is IIT KGP?

Lol bro, u r on the edge of pupil-newbie

When the guy who steals your meme gets more upvotes than you.

Reference: https://codeforces.com/blog/entry/102996?#comment-914421

Good luck

Yes, it is rated for all divisions.

Wishing you luck, to solve even more

All the best

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some moderate amount of math is fine, last time it was kinda excessive but the problems were very interesting

It's IND vs SL!

Color everything in blue. Now do a DFS from node 1. Since m is at most n+2, you will get at most 3 back edges. Store those back edges while traversing by dfs.

Now you have obtained some tree rooted in node 1, with some back edges. Now if you have less than 3 back edges, simply color those back edges as red.

If you have 3 back edges, and they form a triangle, in other words have form a-b, b-c, a-c, color a-b and b-c as red. Now look at a-c. Coloring this as red would be a waste, because a, b, c are already connected. So instead leave it as blue. Find out whether a or c has a greater depth in the DFS tree. Let’s say d = deepest(a, c). Color the edge d and parent[d] in red. This way we preserve the tree structure of the blue subgraph and decrement the number of connected components in the red subgraph.

If you have 3 back edges that do not form such a triangle/cycle. Just color them in red.

I highly suggest drawing a tree structure with back edges to understand it better.

Look at number of index i, such that s[i]='(' and s[i+1]!=')'

I just use DSU.

the number of positions such that s[i] = s[i+1] = ')'

Can't agree more.

Wut it's easier than A, I'm mad because of B not saying it's hard but I'm so stupid and slow

i messed up preety badly at c

Any hints for D?

By the way , The $$$O(n\times \sqrt{nlog_2n})$$$ solution may be easier to implement.

I also failed it, my approach was this:

1. use union find to color all red without loops

2. at the end at most 3 blue edges will be left over

3. if those three blue edges happen to form a loop, swap the last blue edge with one of the red edges -> there will be no blue loop any more

4. my problem was I didn't know how to select the correct red edge to swap with, since for some red edges you will create a red-cycle

Same here. 256MB is unnecessarily too tight! Lose the chance to gain rating.

My ST table didn't get MLE.

However, I forgot to check whether there's a time which can reach n without passing any red lights and got WA on test 7. What a pity.

Make MST. Pick the $$$m-(n-1)$$$ edges not in MST. Only when $$$m = n+2$$$ can these edges create a cycle. If they do, then take one edge and transfer it to other color and the edge to its parent to current color, provided that the swapped edge is not in its subtree.

$$$1,2,3,5$$$ was one component, $$$4$$$ was the other

How to solve E? I thought its about calculating sums of $$$\frac{P^n_{2k}}{2^k k!}$$$ or smth for $$$1\leq k \leq \lfloor \frac{n}{2} \rfloor$$$

(sorry about the big text, things were becoming unreadable)

@u1602016 You are not decrementing variable t, so it continues to loop forever :)

Same problem. TLE with Python/PyPy3 (pretest 4), OK with C++ (system testing). Slow input/output in Python, maybe.

Is it possible to get pretest 4 for experiments?

Submission https://codeforces.com/contest/1726/submission/171110352 Room (with the other submissions with slightly smodified input/output) https://codeforces.com/contest/1726/room/464

@u1602016 yes, the problem is with the slow I/O in python as it takes 5-10 times more to run compare to c/c++.

For the cross-check part I have also converted your solution in c++, and tried to submit, and it works perfectly fine within time(561ms, note: your solution is correct) here

Solution??? you could either use the fast I/O for python while doing CP (as @Varad2002 mentioned) or you could use c++ for CP (I would personally recommend this, as I have experienced the situation where my JAVA code throws TLE (even after using fast I/O) whereas same algorithm works within time limit in C++)

)(

Look at cycle decomposition of $$$p$$$.

We tried our best to break such solutions, but it seems it was not enough :(