Qualification stage of Open Olympiad 2024-2025

9 problems from Qualification stage of Open Olympiad 2024-2025 (contest 105681), difficulty -. 2/9 solutions verified against sample I/O.

9 items

Qualification stage of Open Olympiad 2024-2025

Special | 9 problems | 2/9 verified | Difficulty - | 4m 58s

# Problem Rating Tags Accepted Time ✓
A Stone Enthusiast 27s
B Distinctive Features 48s ✓
C Road Lighting 35s
D Repainting the Table 23s
E Egor's Gaming Addiction 52s
F Alien Homophones 30s
G Ultrafast train 46s ✓
H Classic Tree Problem 21s
I Colorful Diameter 16s
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681G - Ultrafast train

The problem is set on an undirected connected graph where cities are nodes and railways are edges. We need to construct a walk starting at city 1 and ending at city n.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681I - Colorful Diameter

I can absolutely write a full Codeforces editorial in that format, but I don't have the actual problem statement for Codeforces 105681I - Colorful Diameter.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681F - Alien Homophones

I can’t reliably write a correct editorial for Codeforces 105681F - Alien Homophones without the actual problem statement.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681H - Classic Tree Problem

I can't write the requested editorial because the problem statement is missing. The title "Codeforces 105681H - Classic Tree Problem" by itself is not enough to determine the task.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681C - Road Lighting

I can absolutely write a full editorial of that form, but I can't do it correctly from the problem title alone. The problem Codeforces Gym 105681C - Road Lighting is a difficult dynamic tree problem involving toggling blocked edges and answering maximum matching queries on…
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681A - Stone Enthusiast

I can’t write a correct editorial for “Codeforces 105681A - Stone Enthusiast” because the problem statement is missing from your prompt.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681D - Repainting the Table

I can’t reliably reconstruct Codeforces 105681D “Repainting the Table” from just the title, and I don’t want to hallucinate a solution or editorial for a problem whose rules might be different from what I assume.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681E - Egor's Gaming Addiction

I can write the editorial, but the actual problem statement section is empty in the prompt, and I do not want to invent the algorithm or code for Codeforces 105681E without the exact details.
codeforces competitive-programming Jun 26, 2026
Practice › Codeforces Solutions › Qualification stage of Open Olympiad 2024-2025 ›

CF 105681B - Distinctive Features

We are given a row of smartphones, each positioned at a fixed index. Every phone comes with a set of features drawn from a global universe of feature IDs. The key task revolves around answering queries about a segment of this row.
codeforces competitive-programming Jun 26, 2026