Educational Codeforces Round 92 (Rated for Div. 2)

7 problems from Educational Codeforces Round 92 (Rated for Div. 2) (contest 1389), difficulty 800-2800. 2/7 solutions verified against sample I/O.

7 items

Educational Codeforces Round 92 (Rated for Div. 2)

Div. 2 | 7 problems | 2/7 verified | Difficulty 800-2800 | 27m 24s

# Problem Rating Tags Accepted Time ✓
A LCM Problem 800 constructive-algorithms, greedy, math 49,851 5m 28s
B Array Walk 1600 brute-force, dp, greedy 20,339 1m 57s ✓
C Good String 1500 brute-force, dp, greedy 20,560 5m 10s
D D 2100 brute force, greedy, implementation 4,553 4m 57s
E Calendar Ambiguity 2200 math, number-theory 3,724 5m
F Bicolored Segments 2600 data-structures, dp, graph-matchings 1,246 2m 17s ✓
G Directing Edges 2800 dfs-and-similar, dp, graphs 495 2m 35s
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CF 1389E - Calendar Ambiguity

We are given a fictional calendar system where time is structured in three layers. A year has m months, every month contains exactly d days, and the week repeats every w days.
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CF 1389G - Directing Edges

We are given an undirected connected graph where each edge can be turned into a one-way edge of our choosing or kept as a two-way edge. Keeping it two-way is expensive, since every such edge contributes its weight to the cost.
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CF 1389A - LCM Problem

We are given many independent ranges of integers. For each range $[l, r]$, we need to pick two different integers $x$ and $y$ inside this interval such that their least common multiple is also inside the same interval.
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CF 1389C - Good String

We are given a string of digits and allowed to delete characters anywhere we like, preserving order of the remaining ones. The goal is to transform the string into a special form called “good”.
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CF 1389F - Bicolored Segments

We are given a set of segments on the number line, each colored either 1 or 2. A pair of segments is considered bad if they overlap or touch and have different colors. Our goal is to select as many segments as possible while avoiding any bad pair.
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CF 1389B - Array Walk

We are asked to simulate a walk along an array of positive integers, starting at the first element. Each move can either go one step to the right, which is always allowed if we are not at the last element, or one step to the left, which can only be done if we are not at the…
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