Codeforces Global Round 28

10 problems from Codeforces Global Round 28 (contest 2048), difficulty 800-3500. 1/10 solutions verified against sample I/O.

10 items

Codeforces Global Round 28

Global | 10 problems | 1/10 verified | Difficulty 800-3500 | 23m 4s

# Problem Rating Tags Accepted Time ✓
A Kevin and Combination Lock 800 brute-force, greedy, implementation 22,851 1m 14s ✓
B Kevin and Permutation 900 constructive-algorithms, greedy 20,647 4m 32s
C Kevin and Binary Strings 1200 bitmasks, brute-force, greedy 15,138 1m 48s
D Kevin and Competition Memories 1600 binary-search, brute-force, data-structures 8,307 1m 55s
E Kevin and Bipartite Graph 2000 constructive-algorithms, graphs, greedy 3,501 3m 18s
F Kevin and Math Class 2500 brute-force, data-structures, divide-and-conquer 1,318 1m 35s
G Kevin and Matrices 2800 brute-force, combinatorics, dp 742 3m 13s
H Kevin and Strange Operation 3100 data-structures, dp 248 1m 45s
I1 Kevin and Puzzle (Easy Version) 3500 constructive-algorithms 103 2m 5s
I2 Kevin and Puzzle (Hard Version) 3500 bitmasks, fft, math 57 1m 39s
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CF 2048I2 - Kevin and Puzzle (Hard Version)

We are asked to count arrays of non-negative integers that satisfy conditions imposed by a string of L and R characters.
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CF 2048G - Kevin and Matrices

There is not enough information to diagnose the algorithm from the sample alone. The input contains only pairs (n, k), and the expected outputs are permutations: Many different Codeforces and contest problems use exactly this input format and require constructing a permutation…
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CF 2048I1 - Kevin and Puzzle (Easy Version)

We are asked to construct an array of non-negative integers corresponding to a string of directions, where each character in the string specifies a condition about the count of distinct numbers in either the prefix or suffix of the array.
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CF 2048H - Kevin and Strange Operation

We are given a binary string s composed of 0s and 1s. Kevin can repeatedly perform a special operation: choose a position p, replace every character before it with the maximum of itself and the next character, then remove the character at position p.
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CF 2048E - Kevin and Bipartite Graph

We are asked to design a bipartite graph for a poster pattern. The left part has $2n$ vertices, and the right part has $m$ vertices, with every left vertex connected to every right vertex. Each edge must be colored with an integer between $1$ and $n$.
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CF 2048F - Kevin and Math Class

We are given two arrays of the same length. The first array represents the values we want to eventually reduce to ones, and the second array controls how fast we can reduce segments. A single operation chooses a contiguous segment.
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CF 2048B - Kevin and Permutation

The reported failure is not caused by the algorithm's logic. The traceback shows: at: This means that somewhere before the call, the name solve was overwritten with None: or equivalently: and then later: was executed.
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CF 2048D - Kevin and Competition Memories

We are given a fixed list of problem difficulties and a list of participant ratings. If a participant has rating $ai$, they solve exactly those problems whose difficulty is at most $ai$.
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CF 2048C - Kevin and Binary Strings

We are given a binary string where the first character is always 1. From this string, we must pick two non-empty substrings, and we are allowed to pick the same substring twice or pick overlapping ones.
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CF 2048A - Kevin and Combination Lock

We are given a starting integer and a small set of operations that modify it. The goal is to determine whether we can eventually reduce the number exactly to zero. The two operations behave very differently.
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