2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred)
12 problems from 2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred) (contest 1773), difficulty 800-3500. 5/12 solutions verified against sample I/O.
2022-2023 ICPC, NERC, Northern Eurasia Onsite (Unrated, Online Mirror, ICPC Rules, Teams Preferred)
ICPC/IOI | 12 problems | 5/12 verified | Difficulty 800-3500 | 33m 11s
| # | Problem | Rating | Tags | Accepted | Time | ✓ |
|---|---|---|---|---|---|---|
| A | Amazing Trick | 1900 | constructive-algorithms, graph-matchings, math | 1,906 | 2m 23s | |
| B | BinCoin | 2200 | binary-search, divide-and-conquer, hashing | 973 | 2m 27s | |
| C | Cactus Meets Torus | 3500 | 41 | 1m 6s | ✓ | |
| D | Dominoes | 2600 | combinatorics, flows, graph-matchings | 640 | 1m 49s | ✓ |
| E | Easy Assembly | 1400 | greedy, sortings | 6,089 | 2m 6s | ✓ |
| F | Football | 800 | constructive-algorithms | 4,778 | 5m 22s | |
| G | Game of Questions | 2800 | bitmasks, combinatorics, dp | 547 | 4m 17s | ✓ |
| H | Hot and Cold | 2600 | binary-search, interactive | 494 | 2m 18s | |
| I | Interactive Factorial Guessing | 2500 | brute-force, games, implementation | 579 | 2m 18s | |
| J | Jumbled Trees | 2900 | constructive-algorithms, math | 140 | 3m 16s | |
| K | King's Puzzle | 1900 | constructive-algorithms | 1,676 | 1m 12s | ✓ |
| L | Lisa's Sequences | 3500 | dp | 105 | 4m 37s |
CF 1773L - Lisa's Sequences
We are given a sequence of integers and a fixed length $k$. The task is to modify the sequence as little as possible so that it no longer contains any contiguous block of length exactly $k$ that is monotone.
CF 1773J - Jumbled Trees
Each edge in a connected undirected graph carries a value that starts at zero. We are allowed to perform operations, and each operation picks a spanning tree of the graph and adds a single chosen value $v$ to every edge in that tree.
CF 1773F - Football
We are given aggregated statistics for a football team over a sequence of matches. Instead of knowing individual match results, we only know three numbers: how many matches were played, how many total goals the team scored across all matches, and how many total goals it conceded.
CF 1773I - Interactive Factorial Guessing
We are interacting with a hidden integer $n$, but we are not allowed to see it directly. Instead, we can ask up to 10 questions of the form: “what is the $k$-th digit from the right of $n!$ in decimal representation?”.
CF 1773H - Hot and Cold
We are playing a coordinate guessing game on a large integer grid. There is a hidden target point somewhere in the square from $(0,0)$ to $(10^6,10^6)$.
CF 1773B - BinCoin
We are given a rooted binary tree with $n$ employees. Each employee has either zero or two direct subordinates, and there is a unique root (the CEO).
CF 1773A - Amazing Trick
We are given a permutation $a$ of size $n$, meaning every number from $1$ to $n$ appears exactly once. We are allowed to apply two permutations $q$ first and then $p$, so that the final position $i$ receives the value originally at position $p[q[i]]$.
CF 1773E - Easy Assembly
We are given several vertical stacks of uniquely numbered blocks. Each stack is ordered from top to bottom, and we are allowed to physically reorganize these blocks using two operations: we can cut a stack into two by taking a prefix or suffix segment and turning it into a new…
CF 1773K - King's Puzzle
Thank you for the clarification. Let’s carefully trace why the previous solution produced 2.0 instead of 1.0 for the input: Participant 1 is Genie. The mask of the only question is: So mask = 0b11010 = 26. The initial alive set is all participants: S = 0b11111 = 31.
CF 1773G - Game of Questions
Each test case gives a binary matrix with up to 17 columns and up to 2⋅10^5 rows. Each column represents a participant, and each row describes which participants would answer a particular question correctly. The questions are randomly permuted before being asked.
CF 1773D - Dominoes
Now we finally see a real logical failure rather than a wrapper issue. The produced output: is structurally consistent but numerically wrong, which tells us the implementation is computing something uniform per position instead of position-dependent reachability.