Codeforces Round 930 (Div. 1)

Solutions for Codeforces Round 930 (Div. 1) (contest 1936). 1/6 problems verified against sample I/O. Difficulty range: 1700-3400.

6 items

Codeforces Round 930 (Div. 1)

Type: Div. 1 | Problems: 6 | Verified: 1/6 | Rating range: 1700-3400 | Time: 15m 24s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Bitwise Operation Wizard	1700	bitmasks, constructive-algorithms, greedy	2m 1s	✗
B	Pinball	2000	binary-search, data-structures, implementation	2m 22s	✗
C	Pok\u00e9mon Arena	2400	data-structures, graphs, greedy	1m 47s	✓
D	Bitwise Paradox	3100	binary-search, bitmasks, data-structures	4m 3s	✗
E	Yet Yet Another Permutation Problem	3400	divide-and-conquer, fft, math	2m 56s	✗
F	Grand Finale: Circles	3300	binary-search, geometry	2m 15s	✗

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CF 1936D - Bitwise Paradox

We are given two arrays a and b of length n and a target integer v. The array b represents values on which we perform bitwise OR operations over subarrays. An interval [l, r] is “good” if the bitwise OR of all bi in that interval is at least v.

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CF 1936E - Yet Yet Another Permutation Problem

We are asked to count permutations $q$ of length $n$ such that at every position $i < n$, the maximum of the first $i$ elements in $q$ is different from the maximum of the first $i$ elements in a given permutation $p$.

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CF 1936F - Grand Finale: Circles

We are given several disks on a 2D plane. Each disk defines a constraint: any valid solution circle must lie completely inside it.

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CF 1936B - Pinball

We are asked to simulate a pinball moving on a one-dimensional grid of length $n$, where each cell has an arrow, either '<' pointing left or '' pointing right. The pinball moves according to the arrow on the current cell, and after each move, the arrow it left behind flips.

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CF 1936A - Bitwise Operation Wizard

We are given a hidden permutation of numbers from 0 to $n-1$. Our task is to identify two indices $i$ and $j$ such that the XOR of the values at these positions, $pi oplus pj$, is as large as possible. Direct access to the permutation is forbidden, but we can query an oracle.

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CF 1936C - Pokémon Arena

We are given a set of Pokémon, each described by a vector of attributes and a hiring cost. Initially, only Pokémon 1 is active in the arena. The goal is to eventually make Pokémon n become the active one. We can move through Pokémon by “duels”.