Educational Codeforces Round 170 (Rated for Div. 2)

Solutions for Educational Codeforces Round 170 (Rated for Div. 2) (contest 2025). 4/7 problems verified against sample I/O. Difficulty range: 800-3000.

7 items

Educational Codeforces Round 170 (Rated for Div. 2)

Type: Div. 2 | Problems: 7 | Verified: 4/7 | Rating range: 800-3000 | Time: 23m 14s

Problem Name Rating Tags Solve Time Verified
A Two Screens 800 binary-search, greedy, strings 3m 11s ✓
B Binomial Coefficients, Kind Of 1100 combinatorics, dp, math 7m 17s ✗
C New Game 1300 binary-search, brute-force, greedy 5m 4s ✗
D Attribute Checks 1800 brute-force, data-structures, dp 1m 22s ✓
E Card Game 2200 combinatorics, dp, fft 2m 48s ✓
F Choose Your Queries 2700 constructive-algorithms, dfs-and-similar, dp 2m 9s ✗
G Variable Damage 3000 data-structures, flows 1m 23s ✓
Practice › Codeforces Solutions › Educational Codeforces Round 170 (Rated for Div. 2) ›

Practice › Codeforces Solutions › Educational Codeforces Round 170 (Rated for Div. 2) ›

CF 2025C - New Game

The game revolves around a deck of cards, each labeled with an integer. Monocarp can start by taking any card. On subsequent turns, he can only take a card that either has the same number as the last card taken or is exactly one greater.
codeforces competitive-programming binary-search brute-force greedy implementation sortings two-pointers Jun 9, 2026
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CF 2025F - Choose Your Queries

For a polynomial $f$ of degree $n$, define $Fk(x)=sum{j=0}^{k}f(x+j).$ The dependence on $k$ is described by Faulhaber's formulas.
codeforces competitive-programming constructive-algorithms dfs-and-similar dp graphs greedy trees Jun 9, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 170 (Rated for Div. 2) ›

CF 2025E - Card Game

The core issue is not a boundary bug or a missing case. The previous approach was fundamentally overconstrained: it tried to force both segments to be aligned with axes and also tied them to a single corner or a simplistic placement rule.
codeforces competitive-programming combinatorics dp fft greedy math Jun 8, 2026
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CF 2025G - Variable Damage

The problem models a turn-based battle between a dragon and an army of heroes protected by artifacts. Each hero has a health value and each artifact has a durability value. A hero can hold at most one artifact, and artifacts can only protect heroes while they are active.
codeforces competitive-programming data-structures flows Jun 8, 2026
Practice › Codeforces Solutions › Educational Codeforces Round 170 (Rated for Div. 2) ›

CF 2025D - Attribute Checks

We are given a sequence of game records where each element represents either acquiring an attribute point or encountering an attribute check. The character starts with Strength and Intelligence at zero.
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CF 2025A - Two Screens

We are given two screens that can each display sequences of uppercase letters. Initially both screens are empty. At each second, we can either append a single letter to one of the screens, or copy the entire sequence from one screen to the other, replacing what was on the…
codeforces competitive-programming binary-search greedy strings two-pointers Jun 8, 2026