Codeforces Beta Round 17

5 problems from Codeforces Beta Round 17 (contest 17), difficulty 1000-2900. 4/5 solutions verified against sample I/O.

5 items

Codeforces Beta Round 17

Beta | 5 problems | 4/5 verified | Difficulty 1000-2900 | 16m 51s

# Problem Rating Tags Accepted Time ✓
A Noldbach problem 1000 brute-force, math, number-theory 21,391 1m 46s ✓
B Hierarchy 1500 dfs-and-similar, dsu, greedy 6,085 1m 34s ✓
C Balance 2500 dp 1,026 6m 37s
D Notepad 2400 number-theory 1,327 3m 4s ✓
E Palisection 2900 strings 1,990 3m 50s ✓
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CF 17A - Noldbach problem

We are given two integers, n and k. We look at all prime numbers from 2 up to n. Among those primes, we want to count how many can be written in the form:
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CF 17B - Hierarchy

We have employees and directed supervisor offers between them. An offer (a, b, c) means employee a is willing to supervise employee b for cost c. Qualifications are strictly decreasing along every offer, so q[a] > q[b].
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CF 17C - Balance

We are given a string consisting of characters a, b, and c, and we are allowed to repeatedly perform two types of operations: copy the left character of any adjacent pair onto the right, or copy the right character onto the left.
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CF 17D - Notepad

Nick wants to list all numbers of a given length n in base b, where digits range from 0 to b-1, but numbers cannot start with 0. Each page in his notepad holds exactly c numbers. We are asked to compute how many numbers appear on the last page he fills.
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CF 17E - Palisection

We are given a string and we consider every palindromic substring inside it. Each occurrence matters separately, even if two substrings have the same text. For example, in "aaa" there are three different occurrences of "a".
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