Hello Codeforces!

It's been a long time since I posted a lesson in EDU section. Sorry about that, was quite busy managing my course on Youtube.

New lesson is about two pointers method.

What topics you want to learn next? I would prefer topics not covered in my Youtube course, something more specific for competetive programming. Any ideas?

More about EDU section you can read in this post.

Thanks to Stepavly and Supermagzzz for their help with lecture notes and testing problems.

Enjoy the lesson and good luck on the contests!

This is epic!

Suggestions for future topics: Tries, Ternary search, Trees

Also I noticed that this lesson and this lesson are only available in Russian. It would be good if they can be translated into English so more people can learn. Thanks!

Ternary Search Please

Hi! Ternary search is not much important if you know binary search. Ternary search problems can also be solved using binary search. In binary search you will go the mid element and check for the previous and next element and based on your check condition you can either go to left or right.

You can't do that if the values can be non-integer.

I am just asking in curiosity. Even if the values are non-integer, and the error allowed in the problem is 'delta' (let which is generally 1e-6). Then can't we check for mid+delta and mid-delta and then eliminate half part according to the check condition.

You just explained terrnary search, the only difference is that usually in terrnary search the values you mentioned (mid-delta, mid+delta) are selected in a way that they divide the range into 3 equal parts (that's why it's ternary), which makes the code better and less likely to fail because of precision errors.

Thanks for this. Suggestions : Graphs topics like Trees, DP on Trees, etc.

FFT please! By the way, i appreciate your work.

Sqrt Decomposition please

I am not sure but do we need it when we have segtrees?

i guess there are some differences on memory usage and time complexity witch makes it better than segtree in some cases.

Yes, of course. Square root decomposition can handle some types of queries that segment tree can't (or at least it isn't clear that you can handle them).

My suggestion would be Number Theory and Combinatorics.

Epic !! Next courses suggestion — Tries

what about SCC and topological sort, or 2-sat?

Combinatorics, and NOT dp

Combinatorial counting theory please.

string

Your content is great and very easy to understand! I think more lectures in some hard DP topics (e.g. DP knapsack on Tree, DP on Trie, DP Sum over subsets) or maybe some problems that are a combination of simpler algorithms (like, greedy + DAG, bitmask + shortest paths ...) would be very helpful for a lot of people that know all of the basics, yet struggling to apply them into actual problems.

PLEASE DO A COURSE ON COMPUTATIONAL GEOMETRY