1. I created this list on 2026/04/30, and retrospective inclusion of problems (that were solved by me in the past) will obviously select for different things relative to the problems I solve hereafter.
2. I must also stress that this list isn't ordered by any metric (including solve date or quality).
3. As a matter of principle, this list will not contain any problem that I didn't solve unassisted.

Problem	Comments
https://codeforces.com/contest/1458/problem/F	A couple of nice observations around diameters
https://codeforces.com/contest/1583/problem/G	Cute
https://codeforces.com/problemset/problem/2128/F	Just beautiful
https://codeforces.com/contest/2068/problem/E	Surprisingly good for an ICPC problem
https://codeforces.com/problemset/problem/1810/G	One of the problems of all time (?)
https://codeforces.com/contest/1548/problem/E	Working memory test
https://codeforces.com/contest/2021/problem/E3	A lot of little subproblems
https://codeforces.com/contest/1973/problem/F	Memorable to me because my solution for this was hilariously contrived
https://codeforces.com/contest/2164/problem/F2	Beautiful, I was stuck on this for a while
https://codeforces.com/contest/1981/problem/E	Easy but I like how trivial it becomes with a certain geometric visualization
https://codeforces.com/contest/1562/problem/F	Nice
https://codeforces.com/contest/1710/problem/D	I distinctly remember solving this (I was extremely depressed for a few weeks while at home, and this problem made me quite happy for a while)
https://codeforces.com/problemset/problem/1819/E	I was really depressed when I solved this too. I don't think this problem is as hard as its rating implies.
https://codeforces.com/contest/1827/problem/E	I'm a sucker for small-to-large merging. Also, I was quite weak when I solved this.
https://codeforces.com/contest/2147/problem/F	Elegant
https://codeforces.com/problemset/problem/1654/F	There's an extraordinarily elegant solution, and there's an extraordinarily inelegant solution
https://codeforces.com/contest/1062/problem/F	I solved this a long time ago and remember being shocked when I realized the solution
https://codeforces.com/contest/2228/problem/E1	Cute interleaving argument
https://codeforces.com/contest/1975/problem/F	Surprising solution
https://codeforces.com/contest/1430/problem/G	Cute
https://codeforces.com/contest/1408/problem/G	I have no shame, I must put this here...