My website

Today I’ll talk about a standard C++ data structure that is amazing: the bitsets. They can handle binary operations such as left shift («), right shift (»), and (&), or (|), and xor (^), and they can have a fixed number of bits. Now you may ask me which types... [Read More]

There is a class of graphs called Perfect Graphs for which some problems can be solved in polynomial time, such as: maximum clique, maximum independent set, and coloring. One such graph is the Split Graph, which can be checked by a simple $O(|V| \log |V|)$ algorithm, by simply checking if... [Read More]

Today I’ll talk about a problem from Beecrowd called Flea Circus. I solved this problem using a Treap (I recommend reading this article), and the implementation is very straightforward if you are already familiar with the data structure. [Read More]

There is a useful optimization trick involving DP on trees that I would like to discuss. It was detailed in the comments of this Codeforces blog. In short, you can define a DP over the vertices of a tree and compute its value for each $v$-subtree by combining the children... [Read More]

There is a great problem on Kattis called It’s a Mod, Mod, Mod, Mod World with a short statement: given $p$, $q$, and $n$, find $\sum_{i = 1}^{n} \left[ (pi) \bmod q \right]$. [Read More]