Codeforces Round 1040 (Div. 1)

9 problems from Codeforces Round 1040 (Div. 1) (contest 2129), difficulty 1300-3500. 2/9 solutions verified against sample I/O.

9 items

Codeforces Round 1040 (Div. 1)

Div. 1 | 9 problems | 2/9 verified | Difficulty 1300-3500 | 17m 30s

# Problem Rating Tags Accepted Time ✓
A Double Perspective 1300 constructive-algorithms, dp, dsu 16,636 1m 22s ✓
B Stay or Mirror 1600 brute-force, data-structures, dp 13,253 1m 38s
C1 Interactive RBS (Easy Version) 1900 binary-search, bitmasks, constructive-algorithms 3,856 2m 7s
C2 Interactive RBS (Medium Version) 2000 binary-search, bitmasks, constructive-algorithms 2,502 1m 42s
C3 Interactive RBS (Hard Version) 2300 binary-search, bitmasks, constructive-algorithms 1,663 3m 15s
D Permutation Blackhole 2600 brute-force, combinatorics, dp 945 1m 39s
E Induced Subgraph Queries 3000 data-structures, graphs, sortings 476 1m 40s ✓
F1 Top-K Tracker (Easy Version) 3500 interactive 134 2m 26s
F2 Top-K Tracker (Hard Version) 3500 interactive 97 1m 41s
Practice › Codeforces Solutions › Codeforces Round 1040 (Div. 1) ›

CF 2129F2 - Top-K Tracker (Hard Version)

We are given a hidden permutation of integers from 1 to $n$, and we can only access it indirectly through interactive queries. There are four types of queries.
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CF 2129F1 - Top-K Tracker (Easy Version)

We are asked to recover a hidden permutation of the numbers from 1 to $n$ through a limited set of interactive queries.
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CF 2129C3 - Interactive RBS (Hard Version)

We are given a hidden binary string made of opening and closing brackets, and we are allowed to probe it indirectly.
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CF 2129E - Induced Subgraph Queries

We are given a simple undirected graph whose vertices are labeled from 1 to n. The label itself is also the index of the vertex. The graph does not change, but each query focuses only on a contiguous segment of vertices, from l to r.
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CF 2129D - Permutation Blackhole

We are given a permutation of numbers from 1 to $n$, and a process that colors these numbers one by one in the order of the permutation. Each cell starts white with a score of zero.
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CF 2129C2 - Interactive RBS (Medium Version)

We are given a hidden string made only of opening and closing parentheses. We cannot see it directly. Instead, we can query any multiset-like sequence of indices, and the judge constructs a new string by taking the characters at those indices in order.
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CF 2129C1 - Interactive RBS (Easy Version)

We are given a hidden bracket sequence of length $n$, consisting only of '(' and ')'. The goal is to reconstruct this sequence by asking at most 550 interactive queries.
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CF 2129B - Stay or Mirror

We are given a permutation of integers from 1 to n. For each element in this permutation, we are allowed to either leave it as-is or replace it with its “mirror” with respect to 2n, defined as $2n - pi$.
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CF 2129A - Double Perspective

We are given a collection of segments on a line, each segment also acting as an edge between two vertices. From this set we must choose some subset of edges. Two different quantities are computed from the chosen subset.
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