2020-2021 Winter Petrozavodsk Camp, Belarusian SU Contest (XXI Open Cup, Grand Prix of Belarus)
14 problems from 2020-2021 Winter Petrozavodsk Camp, Belarusian SU Contest (XXI Open Cup, Grand Prix of Belarus) (contest 102956), difficulty -. 11/14 solutions verified against sample I/O.
2020-2021 Winter Petrozavodsk Camp, Belarusian SU Contest (XXI Open Cup, Grand Prix of Belarus)
Special | 14 problems | 11/14 verified | Difficulty - | 16m 13s
| # | Problem | Rating | Tags | Accepted | Time | ✓ |
|---|---|---|---|---|---|---|
| A | Belarusian State University | 1m 7s | ✓ | |||
| B | Beautiful Sequence Unraveling | 1m 12s | ✓ | |||
| C | Brave Seekers of Unicorns | 1m 10s | ||||
| D | Bank Security Unification | 46s | ✓ | |||
| E | Brief Statements Union | 2m 30s | ||||
| F | Border Similarity Undertaking | 51s | ✓ | |||
| G | Biological Software Utilities | 42s | ✓ | |||
| H | Bytelandia States Union | 43s | ✓ | |||
| I | Binary Supersonic Utahraptors | 48s | ✓ | |||
| J | Burnished Security Updates | 53s | ✓ | |||
| K | Bookcase Solidity United | 51s | ✓ | |||
| L | Business Semiconductor Units | 2m 36s | ||||
| M | Brilliant Sequence of Umbrellas | 1m 8s | ✓ | |||
| N | Best Solution Unknown | 56s | ✓ |
CF 102956L - Business Semiconductor Units
The Twelvefold Way classifies placements of $n$ balls into $m$ urns according to whether balls and urns are labeled or unlabeled, and whether each urn is unrestricted, required to contain at most one ball, or required to contain at least one ball.
CF 102956N - Best Solution Unknown
We start with a row of participants, each carrying an initial strength value. The process evolves through a sequence of adjacent duels. In every duel, two neighboring players are chosen, the weaker one is removed, and the winner’s strength increases by one.
CF 102956M - Brilliant Sequence of Umbrellas
We are given a large pool of numbered umbrellas from 1 up to n, and we must select a subsequence of distinct numbers arranged in increasing order. The sequence is not arbitrary: it must satisfy a strengthening condition on the greatest common divisor of consecutive elements.
CF 102956K - Bookcase Solidity United
We are given a vertical stack of shelves, each with a durability threshold. The i-th shelf from the top can tolerate only a limited number of balls being on it indirectly through a cascading process. We repeatedly drop identical balls onto chosen shelves.
CF 102956J - Burnished Security Updates
We are given a network of computers connected by undirected cables, and we need to choose a subset of computers to “activate” under two simultaneous rules. First, no two chosen computers are directly connected by a cable, so the chosen set must be independent in graph terms.
CF 102956E - Brief Statements Union
The Twelvefold Way classifies placements of $n$ balls into $m$ urns according to whether balls and urns are labeled or unlabeled, and whether each urn is unrestricted, required to contain at most one ball, or required to contain at least one ball.
CF 102956I - Binary Supersonic Utahraptors
We start with two multisets of items owned by two players. Each item is a utahraptor and each one has a binary color, either yellow or red. Alexey initially owns n utahraptors and Boris owns m. They then play k rounds.
CF 102956H - Bytelandia States Union
We are working on a huge grid, conceptually a 2D lattice with coordinates up to one billion in both directions. A person starts at some cell and wants to reach a designated portal cell using four-directional moves.
CF 102956G - Biological Software Utilities
We are asked to count how many labeled trees on vertices numbered from 1 to n have a special property: the edges of the tree can be partitioned into disjoint pairs of adjacent vertices, meaning every vertex can be matched with exactly one other vertex through edges, after…
CF 102956F - Border Similarity Undertaking
We are given a grid of lowercase letters and we want to count how many axis-aligned rectangles inside this grid have a very strict property on their border: every cell on the boundary of the rectangle must contain exactly the same character.
CF 102956D - Bank Security Unification
We are given a line of routers, each carrying a numeric frequency. We are allowed to select a subsequence of these routers, but the subsequence must contain at least two elements and must preserve the original order.
CF 102956B - Beautiful Sequence Unraveling
We are counting sequences of length $n$, where each position contains an integer between $1$ and $k$. The sequence is declared invalid if there exists a split point $i$ such that the largest value seen in the prefix $a1 dots ai$ is exactly equal to the smallest value seen in…
CF 102956C - Brave Seekers of Unicorns
The solution does not address the stated problem at all. The exercise asks to prove the law of spread/core duality, $$X^{sim +} = X^{circ sim},$$ which is a statement about TAOCP operators on combinatorial objects.