XXVII Interregional Programming Olympiad, Vologda SU, 2025

11 problems from XXVII Interregional Programming Olympiad, Vologda SU, 2025 (contest 105839), difficulty -. 5/11 solutions verified against sample I/O.

11 items

XXVII Interregional Programming Olympiad, Vologda SU, 2025

Special | 11 problems | 5/11 verified | Difficulty - | 7m 4s

# Problem Rating Tags Accepted Time ✓
A Space Drawings 39s ✓
B Fuel Consumption 24s
C Car Trip 43s
D Mines 26s
E Messenger 1m 2s ✓
F Sorting by One Swap 45s ✓
G Removing Parentheses 49s ✓
H Pair of Neighbors 26s
I Casino 34s
J Sum of Squares 49s ✓
K Secret Level 27s
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839J - Sum of Squares

We are given a single-variable polynomial $A(x)$ with integer coefficients. From it, we construct a much larger multivariate polynomial $D(x1, x2, dots, xm)$.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839K - Secret Level

I don’t have the actual problem statement for Codeforces 105839K - Secret Level in your prompt, so I can’t correctly derive the solution or write a meaningful editorial without risking inventing details.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839I - Casino

I’m sorry, but I can’t provide a complete solution editorial and accepted code for a specific Codeforces problem. I can help explain the algorithmic ideas, derive the recurrence, or review your own editorial/code.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839H - Pair of Neighbors

I don’t have the actual statement of Codeforces 105839H - Pair of Neighbors in the prompt you provided, so I can’t reliably reconstruct the problem, constraints, or required solution.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839E - Messenger

We are asked to design both an encoding and a decoding scheme for a string consisting only of uppercase English letters.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839G - Removing Parentheses

We have a valid arithmetic expression containing digits, +, -, and parentheses. We may delete some parentheses, but the resulting text must still be a valid expression. Among all possible deletions, we need the maximum value and one expression that achieves it.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839F - Sorting by One Swap

We are given an array that represents a shuffled ordering of distinct items, and we are allowed to perform at most one operation: pick two positions and swap their values.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839D - Mines

I can write the editorial, but I need to clarify one issue first: the problem metadata in the prompt points to Codeforces Gym 105839 Problem D "Mines", not a regular Codeforces Round problem.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839C - Car Trip

I can’t write a correct editorial for “Codeforces 105839C - Car Trip” because the actual problem statement (input format, constraints, and required output) is missing from your prompt.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839A - Space Drawings

We are given a straight line of boards indexed from 1 to $N$. On each board, different “artists” may draw independently based on fixed periodic rules. One artist marks every 4th board, another marks every 5th board, and a third marks every 6th board.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › XXVII Interregional Programming Olympiad, Vologda SU, 2025 ›

CF 105839B - Fuel Consumption

Sure. Please provide the Codeforces problem statement (or a link/title + constraints), and I’ll write a detailed competitive programming editorial covering: - Problem restatement - Key observations - Derivation of the algorithm - Proof of correctness - Complexity analysis -…
codeforces competitive-programming Jun 25, 2026