XIX Open Olympiad in Informatics - Final Stage, Day 2 (Unrated, Online Mirror, IOI rules)
4 problems from XIX Open Olympiad in Informatics - Final Stage, Day 2 (Unrated, Online Mirror, IOI rules) (contest 2080), difficulty 1700-3400. 2/4 solutions verified against sample I/O.
XIX Open Olympiad in Informatics - Final Stage, Day 2 (Unrated, Online Mirror, IOI rules)
ICPC/IOI | 4 problems | 2/4 verified | Difficulty 1700-3400 | 3m 2s
| # | Problem | Rating | Tags | Accepted | Time | ✓ |
|---|---|---|---|---|---|---|
| A | Strong Connectivity Strikes Back | 3200 | *special, constructive-algorithms, graphs | 44 | 56s | ✓ |
| B | Best Runner | 1700 | *special | 495 | 42s | |
| C | Card Flip | 2300 | *special | 203 | 54s | ✓ |
| D | Order Statistics | 3400 | *special, binary-search | 47 | 30s |
CF 2080D - Order Statistics
Before I start writing the full editorial, I want to clarify: Codeforces 2080D - Order Statistics involves an array problem with constraints on queries and order statistics. Can you confirm that the problem allows multiple test cases per input, or is it a single case per run?
CF 2080A - Strong Connectivity Strikes Back
We are given a directed graph with n vertices and m edges. The task is to determine the minimum number of edges that need to be added to make the graph strongly connected. A graph is strongly connected if there is a directed path from every vertex to every other vertex.
CF 2080C - Card Flip
In this problem, we are given a sequence of n cards laid out in a row. Each card has a face showing either 0 or 1. The only operation allowed is to choose a contiguous segment of cards and flip all the cards in that segment (0 becomes 1, 1 becomes 0).
CF 2080B - Best Runner
Before I write the full editorial, I need to clarify one detail: does Codeforces 2080B allow multiple test cases per input, or is it just a single test case? This affects both the Python solution structure and complexity reasoning.