于心有愧丶

H - Santa Claus and a Place in a Class                   Santa Claus is the first who came to the Christmas Olympiad, and he is going to be the first to take his place at a desk! In the classroo

C - Okabe and Banana Trees Okabe needs bananas for one of his experiments for some strange reason. So he decides to go to the forest and cut banana trees.Consider the point (x, y) in

C - Mahmoud and a Message Mahmoud wrote a message s of length n. He wants to send it as a birthday present to his friend Moaz who likes strings. He wrote it on a magical paper but he w

D - Unfair PollOn the Literature lesson Sergei noticed an awful injustice, it seems that some students are asked more often than others.Seating in the class looks like a rectangle, where n

D - Round SubsetLet's call the roundness of the number the number of zeros to which it ends.You have an array of n numbers. You need to choose a subset of exactly k numbers so that the rou

B - Indivisibility                   IT City company developing computer games decided to upgrade its way to reward its employees. Now it looks the following way. After a new game release users st

E - Hanoi FactoryOf course you have heard the famous task about Hanoi Towers, but did you know that there is a special factory producing the rings for this wonderful game? Once upon a time,

C - Fedor and couponsAll our characters have hobbies. The same is true for Fedor. He enjoys shopping in the neighboring supermarket.The goods in the supermarket have unique integer ids. Al

C. Journeytime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputThere are n cities and n - 1 roads in the Seve

D - Okabe and BoxesOkabe and Super Hacker Daru are stacking and removing boxes. There are n boxes numbered from 1 to n. Initially there are no boxes on the stack.Okabe, being a control fre

D - Average Sleep Time It's been almost a week since Polycarp couldn't get rid of insomnia. And as you may already know, one week in Berland lasts k days!When Polycarp went to a doct

B. Five-In-a-Rowtime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputAlice and Bob play 5-in-a-row game. They ha

C - Patrick and Shopping                    Today Patrick waits for a visit from his friend Spongebob. To prepare for the visit, Patrick needs to buy some goodies in two stores located near his

A - Magic Spheres                   Carl is a beginner magician. He has a blue,b violet and c orange magic spheres. In one move he can transform two spheresof the same color into one sph

A - Santa Claus and Keyboard CheckSanta Claus decided to disassemble his keyboard to clean it. After he returned all the keys back, he suddenly realized that some pairs of keys took each oth

E - Tea Party Polycarp invited all his friends to the tea party to celebrate the holiday. He has ncups, one for each of his n friends, with volumes a1, a2, ..., an. His teapot stores

E - Okabe and City Okabe likes to be able to walk through his city on a path lit by street lamps. That way, he doesn't get beaten up by schoolchildren.Okabe's city is represented by

C. Jury Markstime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputPolycarp watched TV-show where k jury members

E - Mike and gcd problem Mike has a sequence A = [a1, a2, ..., an] of length n. He considers the sequence B = [b1, b2, ..., bn] beautiful if the gcd of all its elements is bigger t

B. Game of the Rowstime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputDaenerys Targaryen has an army consistin

I - NP-Hard ProblemRecently, Pari and Arya did some research about NP-Hard problems and they found theminimum vertex cover problem very interesting.Suppose the graph G is given. Subset A o