As you may have seen, I've written a lot of problems.

In this post, I want to go over each of my problems and describe my thought process for how I created each problem. I got this idea from antontrygubO_o, but I was also inspired by McDic's editorials that included a "behind story" for each problem. Anyway, I thought it would be fun to give you all a glimpse into my thought process: where my ideas came from, the obstacles I encountered along the way, and any random tidbits that give a bit more pizzazz to the problems.

I think it's important to remember that problem-writing is a creative endeavor, so I hope you'll enjoy reading about the making of my problems as much as I enjoyed creating them. And who knows, maybe you'll even be inspired to write some problems of your own.

Also, spoilers for a lot of problems. Obviously.

ID	Problem	Rating	Contest	Comment
001	Domino Disaster	800	Codeforces Round #742	The first problem I ever wrote. I'm firmly in the camp that thinks Div. 2A problems should be more implementation-based rather than random constructions or math formulas, and this is the perfect type of problem to embody that spirit, I think. Easy enough for basically everyone to try and solve.
002	MEXor Mixup	1000	Codeforces Round #742	Actually, this was the first B problem I had seen involving the idea of "precompute answers between test cases", and it seemed to trip a few people up (including LGMs!). Luckily, I was aware of the idea when later problems with similar ideas came around.
003	Carrying Conundrum	1600	Codeforces Round #742	A nice idea, I think, but I wish I would've made the "answer extraction" a little cleaner.
004	Expression Evaluation Error	2000	Codeforces Round #742	This problem was originally proposed as C (and in my opinion, is easier than the above problem). If you want a free 2000, I recommend you do this problem.
005	One-Four Overload	2700	Codeforces Round #742	The first of my "sufficient = necessary" problems.
006	Chef and Pairwise Distances	2012	September Cook-Off 2021	Geometry problem, yay! And it's also the archetype of "large inputs fail".
007	Ones Guessing	N/A	Codechef SnackDown 2021 Final Round	To say the least, I was quite thrilled to see my third contest problem be in Codechef SnackDown finals. It's a funny problem too. Something to think about: how can we write the interactor for this problem to fail every solution except the intended one?
008	Not Shading	800	Codeforces Round #766	Well it looks like I broke my rule about hard/stupid constructive D2A. In my defense, however, I proposed this as D2B, and it was moved down (because the original D2A proposal was... worse, let's just say).
009	Not Splitting	2700	Codeforces Round #766	I think this problem is quite easy, to be honest (I proposed it at E), but perhaps scary geometry terms threw people off. Or maybe it was slightly wrong but technically correct statement at the beginning of contest (because translators changed it like 10 minutes before). Oops.
010	Mango Market	2393	February Cook-Off 2022	Quite goofy problem. I thought of it while studying for an economics exam, hence the flavourtext (the original name was "Monopsonistic Market").
011	Magnet Sort	1804	February Lunchtime 2022	I don't know how to say it, but this is the most generic ad-hoc problem I've ever seen. Yes, that's an oxymoron.
012	Colorful Stamp	1100	Codeforces Round #784	And here come the Div. 4 problems! To be honest, I think it is quite hard to make a Div. 4D, because we're past the "just implement" problems, but it still needs to be easy... I think this problem is too hard for that slot, but somehow it managed to only be 1100.
013	Minimum Crossings (Easy Version) and Minimum Crossings (Hard Version)	1400/1500	Codeforces Round #790	Back when Div. 4 final problem was just "use standard idea". I somewhat regret putting harder version, but I'm a sucker for subtasks.
014	Where's the Bishop?	800	Codeforces Round #799	A simple but natural implementation problem. I'm happy with it.
015	Binary Deque	1200	Codeforces Round #799	Though process behind this problem: "wouldn't it be funny if we had deque in Div. 4?"
016	3SUM	1300	Codeforces Round #799	Very natural and nice problem, and perfect for Div. 4. I like it.
017	2^Sort	1400	Codeforces Round #799	Very unnatural and ugly problem, and not perfect for Div. 4. I still like it.
018	XOR Mixup	800	Codeforces Round #803	Ok so maybe I set goofy problems at D2A. In my defense, you literally can't get this one wrong. By the way, the déjà vu theme of this contest comes from the fact that the titles of each of these problems is a reference to some previous contest, which I don't think anyone saw (except Ari). This one's a reference to MEXor Mixup.
019	Rising Sand	800	Codeforces Round #803	This problem definitely exists, and is a reference to Falling Sand.
020	3SUM Closure	1300	Codeforces Round #803	This problem was added very late to the contest (like, literally, two days before), so unfortunately there were many FSTs because a lot of people used some casework bash(. Testers thought that problem D (which was originally C) was too hard, but I didn't think so. I think I would've been happier with the round without this problem, but hindsight is 20/20. A reference to 3SUM.
021	Fixed Point Guessing	1600	Codeforces Round #803	This would've been a really nice C, I think, but now it's just an easy D. Oh well. The idea is still cute. A reference to Fixed Point Removal.
022	PermutationForces II	2300	Codeforces Round #803	This version of the problem is essentially due to errorgorn, because my original version just had some easy cheese. Also, I don't know why it's 2300, I was worried it was too easy for E. A reference to PermutationForces, obviously.
023	Equal Reversal	2800	Codeforces Round #803	*The best problem I've made.* A surpising result where the obvious necessary condition is not in fact sufficient, and you have to think for a bit more what to do. I originally proposed it at D. Oops. I guess I was warned.
024	Long Binary String	2900	Codeforces Round #803	This problem definitely is one of the problems of all time. Some might call it a knowledge check, but I call it a skill issue. A (very oblique) reference to Long Colorful Strip.
025	YES or YES?	800	Codeforces Round #806	I didn't know what YES or YES was, until I saw it on one of v_Enhance's handouts. I still don't get K-Pop.
026	ICPC Balloons	800	Codeforces Round #806	The only way to make a goofy implementation problem is to write one about the king of goofy implementation problems themselves.
027	Yet Another Problem About Pairs Satisfying an Inequality	1300	Codeforces Round #806	I tried to make a problem with a title longer than the statement. I got close.
028	Colourblindness	800	Codeforces Round #817	I legitimately don't remember making this problem.
029	Word Game	800	Codeforces Round #817	Inspired by Scattergories, of course.
030	Line	1100	Codeforces Round #817	Some random goofy greedy problem to fill in the slot.
031	Seven-Segment Factoring	2675	Starters 59	A nice problem, because it looks super strange but you can get incremental observations that slowly make it more and more approachable. I wish there were subtasks. Sadly, since it was used in a Starters contest, barely anyone saw it(.
032	Sum	800	Codeforces Round #827	uh
033	Stripes	900	Codeforces Round #827	Div. 4C speedbump! More like a brake check actually...
034	Medium Number	800	Codeforces Round #835	ok i literally cannot provide meaningful commentary for D4A
035	Quests	1500	Codeforces Round #835	Another problem made backwards. I was wondering, "we have too many binary search on array problems in Div. 4, but no binary search on the answer..."
036	SSeeeeiinngg DDoouubbllee	800	Codeforces Round #836	Ok I have no excuse for this, but at least this is easier than "here is random formula that trivializes".
037	Almost All Multiples	1400	Codeforces Round #836	A random problem I came up with a few days before the contest to split the constructive problems up. It ended up being basically constructive. Darn.
038	Tick, Tock	2500	Codeforces Round #836	Blame manish.17 for the flavortext. Also, I'm not sure why this is 2500 either, because I originally proposed it at D. Oops.
039	Decent Division	3000	Codeforces Round #836	Cowritten with manish.17; I proposed an easier version where the ratio of ones to zeroes is between $$$0.5$$$ and $$$2$$$. Apparently the same solution could be adapted to this harder version. Somehow, it's the hardest problem I wrote, even though I wrote a harder problem that had to be removed from the contest because we found it elsewhere(.
040	Codeforces Checking	800	Codeforces Round #849	insert witty remark here
041	Following Directions	800	Codeforces Round #849	I'm quite happy with the double entendre of the problem title. The problem itself is a thing that exists.
042	Prepend and Append	800	Codeforces Round #849	I actually like the idea of having concepts like two pointers being given in these implementation problems.
043	Range Update Point Query	1500	Codeforces Round #849	i forgor how i made this problem, but I thought it was nice.
044	Teleporters (Easy Version) and Teleporters (Hard Version)	1100/1900	Codeforces Round #849	I thought of making a problem with sorting by $$$i + a_i$$$, and this popped out.

I do intend to keep this list live as I write more problems. Thanks for reading!