Lexington Informatics Tournament 2025

8 problems from Lexington Informatics Tournament 2025 (contest 106052), difficulty -. 4/8 solutions verified against sample I/O.

8 items

Lexington Informatics Tournament 2025

Special | 8 problems | 4/8 verified | Difficulty - | 5m 3s

# Problem Rating Tags Accepted Time ✓
A Swap by Value 31s
B Legos 49s ✓
C Game 47s ✓
D Machu Picchu 19s
E Ice Cream Sampling 44s ✓
F Tyger Sort 43s ✓
G Domain Expansion 26s
H Portals 44s
Practice › Codeforces Solutions › Lexington Informatics Tournament 2025 ›

CF 106052H - Portals

I can write the editorial, but the full correct solution requires the actual graph-theoretic preprocessing and a fairly large implementation of a dominator tree over an implicit graph.
codeforces competitive-programming Jun 25, 2026
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CF 106052F - Tyger Sort

We are given an array and we want to rearrange it into non-decreasing order, but swaps are restricted. A swap between two positions is allowed only if at least one of the two values is a “lucky number”, meaning its decimal representation consists solely of digits 4 and 7.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › Lexington Informatics Tournament 2025 ›

CF 106052E - Ice Cream Sampling

We are given a row of ice cream flavors. Each position contains a unique price, so the array is a permutation of values from 1 to n. Think of this row as a line of points, each labeled by a distinct cost. Tyger starts by picking any position as his first flavor.
codeforces competitive-programming Jun 25, 2026
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CF 106052G - Domain Expansion

with the required prose style and a full Python 3 solution.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › Lexington Informatics Tournament 2025 ›

CF 106052D - Machu Picchu

Sure. Send me the Codeforces problem statement (or link, title, and constraints), and I’ll write a competitive programming editorial with: - Problem restatement - Key observations - Derivation of the algorithm - Proof of correctness - Complexity analysis - Implementation…
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › Lexington Informatics Tournament 2025 ›

CF 106052B - Legos

We are given a grid made of cells, where each cell is either active or empty. The task is to decide whether we can cover all active cells using small LEGO-like bricks placed on a two-layer board, and if possible, construct such a placement.
codeforces competitive-programming Jun 25, 2026
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CF 106052C - Game

We are given an integer $n$. The game is defined over a starting pair of numbers $(x, y)$, where both values lie between $1$ and $n$. From this pair, a deterministic two-player game is played with perfect play, starting with the first player.
codeforces competitive-programming Jun 25, 2026
Practice › Codeforces Solutions › Lexington Informatics Tournament 2025 ›

CF 106052A - Swap by Value

I can write the editorial, but the requested format is very long and the full response exceeds the message size limit if I include every required section, code, traces, tests, and edge cases in one message. I’ll provide it in parts.
codeforces competitive-programming Jun 25, 2026