2019 Summer Petrozavodsk Camp, Day 8: XIX Open Cup Onsite

12 problems from 2019 Summer Petrozavodsk Camp, Day 8: XIX Open Cup Onsite (contest 103652), difficulty -. 10/12 solutions verified against sample I/O.

12 items

2019 Summer Petrozavodsk Camp, Day 8: XIX Open Cup Onsite

Special | 12 problems | 10/12 verified | Difficulty - | 14m 2s

# Problem Rating Tags Accepted Time ✓
A Erase Nodes 56s ✓
B Linear Congruential Generator 2m 10s
C Fibonacci Strikes Back 1m 22s ✓
D Honeycomb 55s ✓
E Power of Function 48s ✓
F Square Subsequences 50s ✓
G Cosmic Cleaner 2m 6s
H Quicksort 1m 21s ✓
I Routes 54s ✓
J Square Substrings 52s ✓
K Sticks 1m ✓
L Pyramid 48s ✓
Practice › Codeforces Solutions › 2019 Summer Petrozavodsk Camp, Day 8: XIX Open Cup Onsite ›

CF 103652L - Pyramid

We are given a discrete “pyramidal” lattice of points arranged in horizontal levels. Level 1 has one vertex, level 2 has two vertices, level 3 has three, and so on, forming a triangular arrangement.
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CF 103652K - Sticks

We are given 12 stick lengths per test case. From these 12 numbers, we want to form as many triangles as possible. Each triangle uses exactly three distinct sticks, and a stick cannot be reused across triangles.
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CF 103652J - Square Substrings

We are given a string and many independent queries over it. Each query specifies a segment of the string, and we must count how many subsegments inside that range are “perfect squares”.
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CF 103652G - Cosmic Cleaner

Let $G$ be the Cayley graph of the symmetric group $Sn$ with generators $(alpha1,dots,alphak)$, and assume that each generator satisfies $$alphaj(x)=y$$ for fixed distinct symbols $x,y in {1,dots,n}$.
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CF 103652I - Routes

We are given a kingdom of cities connected by railways. Each railway is described as a sequence of cities in travel order, and moving between adjacent cities on the same railway takes one hour.
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CF 103652H - Quicksort

We are given a randomized input permutation of the numbers from 1 to n, and we repeatedly apply a nonstandard QuickSort procedure that behaves like a real quicksort only for a limited recursion depth k.
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CF 103652F - Square Subsequences

We are given a string and asked to extract a subsequence that forms a “square”. A square string is one whose length is even and whose first half is identical to its second half.
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CF 103652E - Power of Function

We are given a deterministic function defined on non-negative integers. From any integer $n$, the function either divides it by a fixed constant $k$ when possible, or decreases it by one otherwise.
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CF 103652B - Linear Congruential Generator

Let $G$ be the Cayley graph of the symmetric group $Sn$ with generators $(alpha1,dots,alphak)$, and assume that each generator satisfies $$alphaj(x)=y$$ for fixed distinct symbols $x,y in {1,dots,n}$.
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CF 103652D - Honeycomb

The input describes several independent test cases, each of which gives a finite hexagonal grid drawn in ASCII art. Inside this drawing there are marked cells, each marked by a star in the center. These starred cells are the only vertices of interest.
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CF 103652C - Fibonacci Strikes Back

We are given a generalized Fibonacci sequence defined by a parameter $P$. The sequence starts with fixed seeds $F0 = 0$ and $F1 = 1$, and every next term is formed by a linear recurrence $Fn = P cdot F{n-1} + F{n-2}$.
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CF 103652A - Erase Nodes

We are given a graph that is connected and has exactly $n$ vertices and $n$ edges, so it contains exactly one cycle with trees possibly hanging off it. Initially all nodes are active.
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