Mail.Ru Cup 2018 Round 2

7 problems from Mail.Ru Cup 2018 Round 2 (contest 1055), difficulty 900-3500. 6/7 solutions verified against sample I/O.

7 items

Mail.Ru Cup 2018 Round 2

Special | 7 problems | 6/7 verified | Difficulty 900-3500 | 22m 6s

# Problem Rating Tags Accepted Time ✓
A Metro 900 graphs 13,441 59s ✓
B Alice and Hairdresser 1300 dsu, implementation 5,541 3m 44s ✓
C Lucky Days 1900 math, number-theory 2,055 2m 17s ✓
D Refactoring 2400 greedy, implementation, strings 649 2m 38s ✓
E Segments on the Line 2500 binary-search, dp 891 6m 10s ✓
F Tree and XOR 2900 strings, trees 605 4m 13s ✓
G Jellyfish Nightmare 3500 104 2m 5s
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CF 1055G - Jellyfish Nightmare

We are given a fixed convex shape representing Bob, which can only move by translation inside a vertical swimming lane bounded by two vertical lines. Bob starts far below the plane and must reach far above it.
codeforces competitive-programming Jun 15, 2026
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CF 1055D - Refactoring

We are given several pairs of strings, where each pair describes how a variable name currently looks and how it should look after a single global refactoring operation.
codeforces competitive-programming greedy implementation strings Jun 15, 2026
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CF 1055C - Lucky Days

Two people have periodic patterns of “good intervals” on the number line of days. Each pattern consists of a fixed segment of consecutive days inside a repeating cycle.
codeforces competitive-programming math number-theory Jun 15, 2026
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CF 1055A - Metro

The metro system can be seen as a line of stations from 1 to n, with two directed ways of movement. One track allows movement from smaller indices to larger ones, while the other allows movement in the opposite direction. Bob starts at station 1 and wants to reach station s.
codeforces competitive-programming graphs Jun 15, 2026
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CF 1055F - Tree and XOR

The tree gives you a system where every vertex can be assigned a value: the XOR of edge weights on the path from an arbitrary root (say vertex 1) to that vertex.
codeforces competitive-programming strings trees Jun 15, 2026
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CF 1055E - Segments on the Line

We are given an array of values laid out on a line, and a collection of candidate intervals on that line. From these intervals, we must pick exactly $m$ of them.
codeforces competitive-programming binary-search dp Jun 15, 2026
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CF 1055B - Alice and Hairdresser

We are maintaining an array of hair lengths on a line of positions, and the system evolves over time as some positions grow.
codeforces competitive-programming dsu implementation Jun 15, 2026