I created video editorial for D. Longest Max Min Subsequence from last Div 2 round, that discusses multiple approaches for this problem, involving data structures like set, map, vector, dequeue, segment tree, stack, and algorithms such as Binary Search, Greedy Algorithms, Next Greater Element, Exchange Argument.

Problems discussed :

1. Check if pattern exists as subsequence in text.
2. Finding lexicographically smallest subsequence with maximal length containing only unique elements.
3. CF2001D: Longest Max Min Subsequence

https://youtu.be/fiiGEH0nb-w?si=j_Q-Z8KGJgKMfrrh

I also created a practice contest that contains all problems mentioned in the video. Here is the link to the contest https://codeforces.com/group/7Dn3ObOpau/contest/545195

The problems are untested, if you see any issues, do let me know.