Good Bye 2021: 2022 is NEAR

Solutions for Good Bye 2021: 2022 is NEAR (contest 1616). 2/8 problems verified against sample I/O. Difficulty range: 800-3500.

8 items

Good Bye 2021: 2022 is NEAR

Type: Special | Problems: 8 | Verified: 2/8 | Rating range: 800-3500 | Time: 13m 52s

Problem Name Rating Tags Solve Time Verified
A Integer Diversity 800 implementation 1m 42s ✗
B Mirror in the String 1100 greedy, strings 1m 37s ✓
C Representative Edges 1500 brute-force, geometry, implementation 1m 26s ✓
D Keep the Average High 2000 dp, greedy, math 2m 24s ✗
E Lexicographically Small Enough 2200 brute-force, data-structures, greedy 1m 40s ✗
F Tricolor Triangles 2900 brute-force, graphs, math 1m 48s ✗
G Just Add an Edge 3500 dfs-and-similar, dp, graphs 1m 44s ✗
H Keep XOR Low 3000 bitmasks, combinatorics, data-structures 1m 31s ✗
Practice › Codeforces Solutions › Good Bye 2021: 2022 is NEAR ›

CF 1616G - Just Add an Edge

The problem presents a directed acyclic graph (DAG) where every edge points from a smaller-numbered vertex to a larger-numbered one.
codeforces competitive-programming dfs-and-similar dp graphs Jun 10, 2026
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CF 1616H - Keep XOR Low

We are asked to count all non-empty subsets of an array where the XOR of every pair of elements does not exceed a given number x. Concretely, if we take any subset of indices from the array, and compute the XOR for every pair of values in that subset, each XOR must be ≤ x.
codeforces competitive-programming bitmasks combinatorics data-structures divide-and-conquer dp math Jun 10, 2026
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CF 1616D - Keep the Average High

We are given an array of integers and a target value x. The task is to select as many elements as possible from this array, with a constraint on consecutive selected elements: any contiguous subarray of length at least two that is entirely selected must have an average at…
codeforces competitive-programming dp greedy math Jun 10, 2026
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CF 1616F - Tricolor Triangles

We are given a small undirected graph where every edge is supposed to end up painted with one of three colors. Some edges are already fixed with a color, while others start uncolored and must be assigned a value in {1, 2, 3}.
codeforces competitive-programming brute-force graphs math matrices Jun 10, 2026
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CF 1616E - Lexicographically Small Enough

We are given two strings of equal length, and we are allowed to modify the first string only by swapping adjacent characters. Each swap costs one operation.
codeforces competitive-programming brute-force data-structures greedy strings Jun 10, 2026
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CF 1616A - Integer Diversity

We are given a list of integers and we are allowed to negate any subset of them. The goal is to maximize the number of distinct integers in the array after possibly negating some elements.
codeforces competitive-programming implementation Jun 10, 2026
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CF 1616B - Mirror in the String

A valid output is constructed by choosing a split point k in a string. After choosing k, the visible string becomes the prefix s[1..k] followed by its reverse. So every candidate answer is a palindrome that is “built from a prefix”.
codeforces competitive-programming greedy strings Jun 10, 2026
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CF 1616C - Representative Edges

We are given an array of integers, and we are allowed to freely replace elements with any real numbers. The goal is to transform the array so that a very strong structural property holds: every subarray must satisfy a linear averaging condition that ties its sum only to its…
codeforces competitive-programming brute-force geometry implementation math Jun 10, 2026