Codeforces Round 839 (Div. 3)

Solutions for Codeforces Round 839 (Div. 3) (contest 1772). 1/7 problems verified against sample I/O. Difficulty range: 800-2200.

7 items

Codeforces Round 839 (Div. 3)

Type: Div. 3 | Problems: 7 | Verified: 1/7 | Rating range: 800-2200 | Time: 14m 59s

Problem Name Rating Tags Solve Time Verified
A A+B? 800 implementation 2m 29s ✗
B Matrix Rotation 800 brute-force, implementation 1m 12s ✗
C Different Differences 1000 constructive-algorithms, greedy, math 3m 21s ✗
D Absolute Sorting 1400 constructive-algorithms, math 3m 22s ✗
E Permutation Game 1700 games 2m 27s ✗
F Copy of a Copy of a Copy 2000 constructive-algorithms, dfs-and-similar, graphs 1m 27s ✓
G Gaining Rating 2200 binary-search, greedy, implementation 41s ✗
Practice › Codeforces Solutions › Codeforces Round 839 (Div. 3) ›

CF 1772G - Gaining Rating

Monocarp wants to increase his chess rating from x to y by playing a set of n opponents with fixed ratings. Each game affects only Monocarp's rating: if his current rating is at least the opponent's, he wins and gains 1; otherwise, he loses and drops 1.
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CF 1772E - Permutation Game

This is a Type B (prove inequality) problem, not Type C. The task is to prove that $$frac1{a^3(b+c)}+frac1{b^3(c+a)}+frac1{c^3(a+b)}ge frac32$$ for all positive $a,b,c$ satisfying $abc=1$.
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CF 1772F - Copy of a Copy of a Copy

We are given a sequence of black-and-white pictures, each represented as an $n times m$ matrix of zeros and ones.
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CF 1772D - Absolute Sorting

We are given a sequence of integers. We are allowed to pick a single real number $x$, and then every element $ai$ is transformed into its distance from $x$, namely $ The task is to determine whether there exists such a choice of $x$, and if it exists, output one valid value.
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CF 1772C - Different Differences

We are asked to build a strictly increasing sequence of length $k$, where every element lies between $1$ and $n$. Among all such sequences, we are not maximizing the values themselves but a derived quantity based on consecutive differences.
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Practice › Codeforces Solutions › Codeforces Round 839 (Div. 3) ›

CF 1772A - A+B?

This is a Type B (prove inequality) problem, not Type C. The task is to prove that $$frac1{a^3(b+c)}+frac1{b^3(c+a)}+frac1{c^3(a+b)}ge frac32$$ for all positive $a,b,c$ satisfying $abc=1$.
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Practice › Codeforces Solutions › Codeforces Round 839 (Div. 3) ›

CF 1772B - Matrix Rotation

We are asked to consider domino tilings of an $8times8$ board. Each domino occupies exactly two adjacent cells and has an orientation, horizontal or vertical.
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