Codeforces Round 845 (Div. 2) and ByteRace 2023

Solutions for Codeforces Round 845 (Div. 2) and ByteRace 2023 (contest 1777). 5/6 problems verified against sample I/O. Difficulty range: 800-2400.

6 items

Codeforces Round 845 (Div. 2) and ByteRace 2023

Type: Div. 2 | Problems: 6 | Verified: 5/6 | Rating range: 800-2400 | Time: 11m 22s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Everybody Likes Good Arrays!	800	greedy, math	1m 33s	✓
B	Emordnilap	900	combinatorics, greedy, math	2m 15s	✓
C	Quiz Master	1700	binary-search, math, number-theory	3m 27s	✓
D	Score of a Tree	1900	bitmasks, combinatorics, dfs-and-similar	1m 33s	✓
E	Edge Reverse	2200	binary-search, dfs-and-similar, graphs	2m	✓
F	Comfortably Numb	2400	bitmasks, data-structures, divide-and-conquer	34s	✗

Practice › Codeforces Solutions › Codeforces Round 845 (Div. 2) and ByteRace 2023 ›

CF 1777E - Edge Reverse

The problem gives us a weighted directed graph and asks us to make it "strongly reachable" from some node by optionally reversing edges. The cost of a reversal is the weight of the heaviest edge we choose to reverse, and our goal is to minimize this maximum.

Practice › Codeforces Solutions › Codeforces Round 845 (Div. 2) and ByteRace 2023 ›

CF 1777F - Comfortably Numb

We are given a sequence of non-negative integers and asked to examine every contiguous segment. For each segment, we compute two values: the bitwise XOR of all elements in the segment, and the maximum element in that same segment.

Practice › Codeforces Solutions › Codeforces Round 845 (Div. 2) and ByteRace 2023 ›

CF 1777C - Quiz Master

We are asked to select a subset of students from a school to form a quiz team. Each student has a smartness value, and each quiz topic requires at least one team member whose smartness is divisible by the topic number.

Practice › Codeforces Solutions › Codeforces Round 845 (Div. 2) and ByteRace 2023 ›

CF 1777D - Score of a Tree

We are given a rooted tree with n nodes. Each node initially holds a value of either 0 or 1. The evolution of values in the tree is defined by a simple rule: at each integer time t 0, every non-leaf node updates its value to the XOR of the values of its children from the…

Practice › Codeforces Solutions › Codeforces Round 845 (Div. 2) and ByteRace 2023 ›

CF 1777B - Emordnilap

We are asked to compute a sum over all permutations of size $n$, where each permutation contributes the number of inversions in a specific array derived from it.

Practice › Codeforces Solutions › Codeforces Round 845 (Div. 2) and ByteRace 2023 ›

CF 1777A - Everybody Likes Good Arrays!

We are asked to transform an array of integers into a “good array,” which is defined as an array where no two consecutive elements share the same parity. Parity simply means whether a number is odd or even.