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At the school where Vasya is studying, preparations are underway for the graduation ceremony. One of the planned performances is a ball, which will be attended by pairs of boys and girls. Each class must present two couples to the ball. In Vasya's class, a boys and b girls wish to participate. But not all boys and not...
codeforces
code_contests
1385
It was the third month of remote learning, Nastya got sick of staying at dormitory, so she decided to return to her hometown. In order to make her trip more entertaining, one of Nastya's friend presented her an integer array a. Several hours after starting her journey home Nastya remembered about the present. To ente...
codeforces
code_contests
1386
Everyone knows that 2010 FIFA World Cup is being held in South Africa now. By the decision of BFA (Berland's Football Association) next World Cup will be held in Berland. BFA took the decision to change some World Cup regulations: * the final tournament features n teams (n is always even) * the first n / 2 teams ...
codeforces
taco
20218
Polycarpus got hold of a family tree. The found tree describes the family relations of n people, numbered from 1 to n. Every person in this tree has at most one direct ancestor. Also, each person in the tree has a name, the names are not necessarily unique. We call the man with a number a a 1-ancestor of the man with ...
codeforces
taco
21535
Dima and his friends have been playing hide and seek at Dima's place all night. As a result, Dima's place got messy. In the morning they decided that they need to clean the place. To decide who exactly would clean the apartment, the friends want to play a counting-out game. First, all the guys stand in a circle, and t...
codeforces
apps
883
One day Greg and his friends were walking in the forest. Overall there were n people walking, including Greg. Soon he found himself in front of a river. The guys immediately decided to get across the river. Luckily, there was a boat by the river bank, just where the guys were standing. We know that the boat can hold pe...
codeforces
taco
1886
As a tradition, every year before IOI all the members of Natalia Fan Club are invited to Malek Dance Club to have a fun night together. Malek Dance Club has 2n members and coincidentally Natalia Fan Club also has 2n members. Each member of MDC is assigned a unique id i from 0 to 2n - 1. The same holds for each member o...
codeforces
taco
282
Mad scientist Mike is building a time machine in his spare time. To finish the work, he needs a resistor with a certain resistance value. However, all Mike has is lots of identical resistors with unit resistance R0 = 1. Elements with other resistance can be constructed from these resistors. In this problem, we will co...
codeforces
taco
1477
Dima, Inna and Seryozha have gathered in a room. That's right, someone's got to go. To cheer Seryozha up and inspire him to have a walk, Inna decided to cook something. Dima and Seryozha have n fruits in the fridge. Each fruit has two parameters: the taste and the number of calories. Inna decided to make a fruit sala...
codeforces
code_contests
1397
Two chess pieces, a rook and a knight, stand on a standard chessboard 8 Γ— 8 in size. The positions in which they are situated are known. It is guaranteed that none of them beats the other one. Your task is to find the number of ways to place another knight on the board so that none of the three pieces on the board bea...
codeforces
taco
10261
Not so long ago as a result of combat operations the main Berland place of interest β€” the magic clock β€” was damaged. The cannon's balls made several holes in the clock, that's why the residents are concerned about the repair. The magic clock can be represented as an infinite Cartesian plane, where the origin correspond...
codeforces
taco
24119
In Berland prime numbers are fashionable β€” the respectable citizens dwell only on the floors with numbers that are prime numbers. The numismatists value particularly high the coins with prime nominal values. All the prime days are announced holidays! Yet even this is not enough to make the Berland people happy. On the...
codeforces
taco
6198
Your friend has recently learned about coprime numbers. A pair of numbers {a, b} is called coprime if the maximum number that divides both a and b is equal to one. Your friend often comes up with different statements. He has recently supposed that if the pair (a, b) is coprime and the pair (b, c) is coprime, then the...
codeforces
apps
563
Amr is a young coder who likes music a lot. He always wanted to learn how to play music but he was busy coding so he got an idea. Amr has n instruments, it takes a_{i} days to learn i-th instrument. Being busy, Amr dedicated k days to learn how to play the maximum possible number of instruments. Amr asked for your he...
codeforces
apps
636
Andrewid the Android is a galaxy-famous detective. He is now investigating a case of frauds who make fake copies of the famous Stolp's gears, puzzles that are as famous as the Rubik's cube once was. Its most important components are a button and a line of n similar gears. Each gear has n teeth containing all numbers f...
codeforces
apps
923
It's election time in Berland. The favorites are of course parties of zublicanes and mumocrates. The election campaigns of both parties include numerous demonstrations on n main squares of the capital of Berland. Each of the n squares certainly can have demonstrations of only one party, otherwise it could lead to riots...
codeforces
taco
5643
Students in a class are making towers of blocks. Each student makes a (non-zero) tower by stacking pieces lengthwise on top of each other. n of the students use pieces made of two blocks and m of the students use pieces made of three blocks. The students don’t want to use too many blocks, but they also want to be uniq...
codeforces
apps
186
Watchmen are in a danger and Doctor Manhattan together with his friend Daniel Dreiberg should warn them as soon as possible. There are n watchmen on a plane, the i-th watchman is located at point (xi, yi). They need to arrange a plan, but there are some difficulties on their way. As you know, Doctor Manhattan consider...
codeforces
taco
9377
During the programming classes Vasya was assigned a difficult problem. However, he doesn't know how to code and was unable to find the solution in the Internet, so he asks you to help. You are given a sequence a, consisting of n distinct integers, that is used to construct the binary search tree. Below is the formal d...
codeforces
code_contests
1410
While creating high loaded systems one should pay a special attention to caching. This problem will be about one of the most popular caching algorithms called LRU (Least Recently Used). Suppose the cache may store no more than k objects. At the beginning of the workflow the cache is empty. When some object is queried ...
codeforces
taco
15313
Tree is a connected undirected graph that has no cycles. Edge cactus is a connected undirected graph without loops and parallel edges, such that each edge belongs to at most one cycle. Vasya has an edge cactus, each edge of this graph has some color. Vasya would like to remove the minimal number of edges in such way ...
codeforces
taco
11317
Misha and Vanya have played several table tennis sets. Each set consists of several serves, each serve is won by one of the players, he receives one point and the loser receives nothing. Once one of the players scores exactly k points, the score is reset and a new set begins. Across all the sets Misha scored a points ...
codeforces
apps
3750
Do you remember a kind cartoon "Beauty and the Beast"? No, no, there was no firing from machine guns or radiation mutants time-travels! There was a beauty named Belle. Once she had violated the Beast's order and visited the West Wing. After that she was banished from the castle... Everybody was upset. The beautiful ...
codeforces
taco
990
<image> Recently, a wild Krakozyabra appeared at Jelly Castle. It is, truth to be said, always eager to have something for dinner. Its favorite meal is natural numbers (typically served with honey sauce), or, to be more precise, the zeros in their corresponding decimal representations. As for other digits, Krakozyabr...
codeforces
taco
18080