Codeforces Round 898 (Div. 4)

Solutions for Codeforces Round 898 (Div. 4) (contest 1873). 6/8 problems verified against sample I/O. Difficulty range: 800-1700.

8 items

Codeforces Round 898 (Div. 4)

Type: Div. 4 | Problems: 8 | Verified: 6/8 | Rating range: 800-1700 | Time: 12m 40s

Problem Name Rating Tags Solve Time Verified
A Short Sort 800 brute-force, implementation 1m 19s ✓
B Good Kid 800 brute-force, greedy, math 1m 48s ✓
C Target Practice 800 implementation, math 1m 36s ✓
D 1D Eraser 800 greedy, implementation, two-pointers 1m 32s ✓
E Building an Aquarium 1100 binary-search, sortings 1m 21s ✓
F Money Trees 1300 binary-search, greedy, math 1m 17s ✓
G ABBC or BACB 1500 constructive-algorithms, greedy 1m 59s ✗
H Mad City 1700 dfs-and-similar, dsu, games 1m 48s ✗
Practice › Codeforces Solutions › Codeforces Round 898 (Div. 4) ›

CF 1873G - ABBC or BACB

We are given a string composed only of the letters A and B, and we are allowed to perform two types of operations on adjacent character pairs. In the first operation, an AB pair can be turned into BC to gain a coin. In the second, a BA pair can be turned into CB to gain a coin.
codeforces competitive-programming constructive-algorithms greedy Jun 8, 2026
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CF 1873H - Mad City

We are asked to determine if one player, Valeriu, can indefinitely avoid being caught by another player, Marcel, in a city modeled as a connected graph with exactly $n$ buildings and $n$ roads. Each building is a node, and each road is an undirected edge connecting two nodes.
codeforces competitive-programming dfs-and-similar dsu games graphs shortest-paths trees Jun 8, 2026
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CF 1873F - Money Trees

We are given a row of trees, each tree carrying two attributes: a height and a number of fruits. We want to choose a contiguous segment of these trees.
codeforces competitive-programming binary-search greedy math two-pointers Jun 8, 2026
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CF 1873E - Building an Aquarium

We are given a row of coral columns, each with some initial height. We want to build a water tank over this structure by choosing a uniform target height $h$.
codeforces competitive-programming binary-search sortings Jun 8, 2026
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CF 1873D - 1D Eraser

We are given a binary string representing a strip of cells, where each position is either black or white. The only operation allowed is choosing any contiguous segment of fixed length $k$ and repainting all cells in that segment to white.
codeforces competitive-programming greedy implementation two-pointers Jun 8, 2026
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CF 1873B - Good Kid

We are given a small collection of digits, and we are allowed to increase exactly one of them by one unit. After this single modification, we compute the product of all digits and want to maximize it.
codeforces competitive-programming brute-force greedy math Jun 8, 2026
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CF 1873C - Target Practice

We are given a $10 times 10$ grid representing a target with five concentric scoring rings. Each cell of the grid either contains an arrow, denoted by X, or is empty, denoted by ..
codeforces competitive-programming implementation math Jun 8, 2026
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CF 1873A - Short Sort

We are given three distinct cards labeled a, b, and c, arranged in some order. Our goal is to determine whether, using at most one swap of two cards, we can transform the row into the ordered sequence abc.
codeforces competitive-programming brute-force implementation Jun 8, 2026