Codeforces Round 1021 (Div. 2)

Solutions for Codeforces Round 1021 (Div. 2) (contest 2098). 2/6 problems verified against sample I/O. Difficulty range: 800-2800.

6 items

Codeforces Round 1021 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 800-2800 | Time: 11m 22s

Problem Name Rating Tags Solve Time Verified
A Vadim's Collection 800 brute-force, greedy 3m 14s ✓
B Sasha and the Apartment Purchase 1400 math, sortings 1m 5s ✓
C Sports Betting 1400 greedy, math, sortings 1m 24s ✗
D Baggage Claim 2300 combinatorics, dfs-and-similar, graphs 2m 45s ✗
E Bermuda Triangle 2400 chinese-remainder-theorem, geometry, number-theory 1m 26s ✗
F Homework 2800 - 1m 28s ✗
Practice › Codeforces Solutions › Codeforces Round 1021 (Div. 2) ›

CF 2098F - Homework

We are given two binary strings of equal length. We are allowed to repeatedly apply a structured operation that splits a string into two halves and then either mixes the halves coordinate-wise using XOR, or recurses into both halves and applies the same process independently.
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CF 2098D - Baggage Claim

Working
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CF 2098E - Bermuda Triangle

We are asked to model a simplified version of the Bermuda Triangle as a right triangle on a 2D coordinate plane, with vertices at $(0,0)$, $(0,n)$, and $(n,0)$. A plane starts inside this triangle at $(x,y)$ and moves with a velocity vector $(vx,vy)$.
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CF 2098C - Sports Betting

Each student fixes a specific day, and Vadim is essentially trying to “predict” what will happen on the next two days after that chosen day.
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CF 2098A - Vadim's Collection

We are given a string of exactly ten digits representing a phone number that satisfies a "beauty" condition: the first digit is at least 9, the second at least 8, and so on down to the last digit, which is at least 0.
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CF 2098B - Sasha and the Apartment Purchase

We are given a line of houses indexed by large integers, and a multiset of bar positions along this line. Multiple bars can occupy the same house, but each bar is treated as a separate point.
codeforces competitive-programming math sortings Jun 8, 2026