Codeforces Global Round 16

Solutions for Codeforces Global Round 16 (contest 1566). 3/9 problems verified against sample I/O. Difficulty range: 800-3200.

9 items

Codeforces Global Round 16

Type: Global | Problems: 9 | Verified: 3/9 | Rating range: 800-3200 | Time: 33m 6s

Problem Name Rating Tags Solve Time Verified
A Median Maximization 800 binary-search, greedy, math 1m 45s ✓
B MIN-MEX Cut 800 bitmasks, constructive-algorithms, dp 5m 8s ✗
C MAX-MEX Cut 1000 bitmasks, constructive-algorithms, dp 9m 22s ✗
D1 Seating Arrangements (easy version) 1100 data-structures, greedy, sortings 1m 52s ✓
D2 Seating Arrangements (hard version) 1600 data-structures, greedy, implementation 2m 25s ✗
E Buds Re-hanging 2000 constructive-algorithms, dfs-and-similar, dp 4m 2s ✗
F Points Movement 2600 data-structures, dp, greedy 2m ✗
G Four Vertices 3100 constructive-algorithms, data-structures, graphs 1m 59s ✓
H Xor-quiz 3200 constructive-algorithms, dp, interactive 4m 33s ✗
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CF 1566H - Xor-quiz

We are given a hidden set $A$ of size $n$, where every element is an integer between $1$ and $c$. We can query any value $x$, and the judge responds with a value computed from the elements of $A$: it takes all $y in A$ that are coprime with $x$, and XORs them together.
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CF 1566G - Four Vertices

We are working with a weighted undirected graph that changes over time by edge insertions and deletions. After every modification, including the initial state, we must look at all pairs of vertices and imagine the shortest path distance between each pair.
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CF 1566C - MAX-MEX Cut

The traceback says: at: So the program is using sys without importing it. This is consistent with the previous correction: we switched to sys.stdin.read() but forgot the required import line: Across previous iterations, there were multiple partial fixes: 1.
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CF 1566E - Buds Re-hanging

We are given a rooted tree with root at vertex 1. A vertex is a leaf if it has no children. A vertex is a bud if it is not the root, has at least one child, and every one of its children is a leaf.
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CF 1566F - Points Movement

We are given a set of starting positions on a number line, each hosting a point that can move left or right in unit steps, each step costing 1. Alongside this, we are given several closed intervals on the same line.
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CF 1566D2 - Seating Arrangements (hard version)

We are tasked with seating nm people in a cinema with n rows and m columns, where the seats in each row are numbered consecutively left to right. Each person has a "sight level," and lower sight levels should get better seats, which are defined as seats with lower indices.
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CF 1566B - MIN-MEX Cut

We are given a binary string and may split it into any number of contiguous pieces. Every character must belong to exactly one piece. For each piece, we compute its MEX.
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CF 1566D1 - Seating Arrangements (easy version)

We are given a line of seats in a single row, labeled from left to right in increasing order. There are $m$ seats, and $nm$ people, but since $n = 1$, we only have one row of length $m$ containing exactly $m$ people in total.
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CF 1566A - Median Maximization

We are asked to determine the largest possible median of an array of n non-negative integers whose sum is exactly s.
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