Codeforces Round 801 (Div. 2) and EPIC Institute of Technology Round
Solutions for Codeforces Round 801 (Div. 2) and EPIC Institute of Technology Round (contest 1695). 4/6 problems verified against sample I/O. Difficulty range: 800-2700.
Codeforces Round 801 (Div. 2) and EPIC Institute of Technology Round
Type: Div. 2 | Problems: 6 | Verified: 4/6 | Rating range: 800-2700 | Time: 13m 10s
| Problem | Name | Rating | Tags | Solve Time | Verified |
|---|---|---|---|---|---|
| A | Subrectangle Guess | 800 | games | 2m 22s | ✓ |
| B | Circle Game | 1000 | games, greedy | 2m 6s | ✓ |
| C | Zero Path | 1700 | brute-force, data-structures, dp | 3m 1s | ✗ |
| D1 | Tree Queries (Easy Version) | 2200 | brute-force, constructive-algorithms, dfs-and-similar | 1m 56s | ✓ |
| D2 | Tree Queries (Hard Version) | 2300 | constructive-algorithms, dfs-and-similar, dp | 1m 40s | ✓ |
| E | Ambiguous Dominoes | 2700 | constructive-algorithms, dfs-and-similar, graphs | 2m 5s | ✗ |
CF 1695E - Ambiguous Dominoes
I can't reliably produce a complete, correct editorial and accepted implementation for Codeforces 1695E from memory alone.
CF 1695D1 - Tree Queries (Easy Version)
We are asked to determine the minimum number of distance queries required to uniquely identify a hidden vertex in a tree. The input gives us a series of trees, each defined by its vertices and edges.
CF 1695D2 - Tree Queries (Hard Version)
We are given an unrooted tree with $n$ vertices. There is a hidden vertex $x$ that we need to identify. The only operation we can perform is a query where we select some vertices and, for each, we receive the distance to the hidden vertex.
CF 1695C - Zero Path
We have a grid whose cells contain only 1 or -1. Starting at the upper-left corner, we may move only right or down until we reach the lower-right corner. Every visited cell contributes its value to the path sum. The task is not to find the number of such paths or the minimum sum.
CF 1695A - Subrectangle Guess
We are given a grid containing distinct integers. Michael chooses dimensions h × w, then Joe secretly selects any subrectangle of exactly that size. Michael must name the maximum value inside Joe's chosen rectangle before seeing which rectangle was selected.
CF 1695B - Circle Game
We are asked to analyze a two-player game played on a circle of stone piles. Each pile has a certain number of stones. Players take turns removing a positive number of stones from the current pile.