Codeforces Round 779 (Div. 2)

7 problems from Codeforces Round 779 (Div. 2) (contest 1658), difficulty 800-2700. 3/7 solutions verified against sample I/O.

7 items

Codeforces Round 779 (Div. 2)

Div. 2 | 7 problems | 3/7 verified | Difficulty 800-2700 | 17m 48s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Marin and Photoshoot	800	constructive-algorithms, implementation, math	20,904	1m 29s	✓
B	Marin and Anti-coprime Permutation	800	combinatorics, math, number-theory	19,542	1m 34s	✓
C	Shinju and the Lost Permutation	1700	constructive-algorithms, math	9,943	4m 10s	✓
D1	388535 (Easy Version)	1600	bitmasks, math	10,000	3m 18s
D2	388535 (Hard Version)	2300	bitmasks, brute-force, data-structures	3,178	2m 48s
E	Gojou and Matrix Game	2500	data-structures, dp, games	1,176	3m
F	Juju and Binary String	2700	brute-force, constructive-algorithms, greedy	922	1m 29s

Practice › Codeforces Solutions › Codeforces Round 779 (Div. 2) ›

CF 1658D1 - 388535 (Easy Version)

We are given a final array that was produced by taking a consecutive integer segment, permuting it, and then applying a fixed XOR mask to every element. The original segment is known to be all integers from l to r inclusive, but their order is scrambled.

Practice › Codeforces Solutions › Codeforces Round 779 (Div. 2) ›

CF 1658E - Gojou and Matrix Game

The game is played on an $n times n$ grid where each cell has a fixed value, and all values are distinct so there are no ties in scoring from identical weights.

Practice › Codeforces Solutions › Codeforces Round 779 (Div. 2) ›

CF 1658D2 - 388535 (Hard Version)

We are given a hidden construction process that starts with a clean consecutive integer segment from some interval $[l, r]$. Gojou first takes all integers in that interval, then shuffles them arbitrarily.

Practice › Codeforces Solutions › Codeforces Round 779 (Div. 2) ›

CF 1658F - Juju and Binary String

We are given a binary string, and we want to select some non-overlapping segments of it whose total length is a specified number, $m$, such that the concatenation of these segments has the same proportion of ones as the original string.

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CF 1658C - Shinju and the Lost Permutation

We are asked to check if a lost permutation could exist given a sequence of "powers" for its cyclic shifts. The power of a permutation is defined by counting distinct elements in the prefix maximum array.

Practice › Codeforces Solutions › Codeforces Round 779 (Div. 2) ›

CF 1658B - Marin and Anti-coprime Permutation

We are asked to count permutations of length $n$ where the greatest common divisor of the sequence $1 cdot p1, 2 cdot p2, dots, n cdot pn$ is strictly greater than 1. Here $p$ is a permutation of integers from 1 to $n$.

Practice › Codeforces Solutions › Codeforces Round 779 (Div. 2) ›

CF 1658A - Marin and Photoshoot

We are given a line of cosplayers represented as a binary string. Each 0 is a male and each 1 is a female. The goal is to ensure that the line is "beautiful," meaning that in every contiguous segment of at least two cosplayers, the number of males does not exceed the number of…