Antipalindrome
A string is a palindrome if it reads the same from the left to the right and from the right to the left. For example, […]
Month: May 2020
Businessmen Problems
Two famous competing companies ChemForces and TopChemist decided to show their sets of recently discovered chemical elements on an exhibition. However they know that no element should be present […]
Useful Decomposition
Ramesses knows a lot about problems involving trees (undirected connected graphs without cycles)! He created a new useful tree decomposition, but he does not know […]
Bookshelves
Mr Keks is a typical white-collar in Byteland. He has a bookshelf in his office with some books on it, each book has an integer […]
Addition on Segments
Grisha come to a contest and faced the following problem. You are given an array of size $n$, initially consisting of zeros. The elements of […]
Round Marriage
It’s marriage season in Ringland! Ringland has a form of a circle’s boundary of length $L$. There are $n$ bridegrooms and $n$ brides, and bridegrooms […]
Magic multisets
In the School of Magic in Dirtpolis a lot of interesting objects are studied on Computer Science lessons. Consider, for example, the magic multiset. If […]
Petr and Permutations
Petr likes to come up with problems about randomly generated data. This time problem is about random permutation. He decided to generate a random permutation […]
Oppa Funcan Style Remastered
Surely you have seen insane videos by South Korean rapper PSY, such as “Gangnam Style”, “Gentleman” and “Daddy”. You might also hear that PSY has […]
Prince’s Problem
Let the main characters of this problem be personages from some recent movie. New Avengers seem to make a lot of buzz. I didn’t watch […]
Perfect Encoding
You are working as an analyst in a company working on a new system for big data storage. This system will store $n$ different objects. […]
Reach Median
You are given an array $a$ of $n$ integers and an integer $s$. It is guaranteed that $n$ is odd. In one operation you can […]
Valid BFS?
The BFS algorithm is defined as follows. Consider an undirected graph with vertices numbered from $1$ to $n$. Initialize $q$ as a new queue containing only vertex $1$, mark […]
Maximum Reduction
Given an array $a$ of $n$ integers and an integer $k$ ($2 \le k \le n$), where each element of the array is denoted by […]
