AGM 2020, Final Round, Day 2

12 problems from AGM 2020, Final Round, Day 2 (contest 102565), difficulty -. 8/12 solutions verified against sample I/O.

12 items

AGM 2020, Final Round, Day 2

Special | 12 problems | 8/12 verified | Difficulty - | 30m 49s

# Problem Rating Tags Accepted Time ✓
A Artifact 58s
B Broken Python 6m 46s ✓
C Flash 3m 37s ✓
D Galleries 5m 51s ✓
E OneZeroTree 1m 3s ✓
F Predictable Tree 1m 2s
G Puppetteer 1m 57s ✓
H Shopping Bags 2m 48s ✓
I Soldiers 1m 22s
J Statue 2m 28s ✓
K Trains 1m 43s
L Trivial 1m 14s ✓
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565B - Broken Python

The task is to evaluate a single mathematical expression written as a string. The expression contains integers, arithmetic operators, and parentheses.
codeforces competitive-programming Aug 7, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565C - Flash

We have an N by N grid. Flash starts in the top left cell. For every distance value d from 1 to 2N-2, we consider all cells that can be reached by repeatedly making moves that go only down or right, where every such move must increase the Manhattan distance from the previous…
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565L - Trivial

We maintain an ordered collection of strings. An update operation appends one lowercase character to one of the existing strings, or creates a new string if the requested position is exactly one after the current collection size.
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565K - Trains

I can’t provide a reliable editorial and implementation for this problem right now because I have not derived the correct algorithm.
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565I - Soldiers

I can write the full editorial, but the requested format is larger than what fits reliably in a single response. I’ll split it into two parts: the first part will cover the problem understanding, approaches, algorithm walkthrough, and proof idea; the second part will contain…
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565F - Predictable Tree

I’m not able to provide a reliable complete editorial and accepted Python solution for this problem from the information available here.
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565E - OneZeroTree

The tree describes all possible routes between pairs of vertices. A route is not enough by itself: every vertex on that route can independently be either active or inactive.
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565A - Artifact

We can view the artifacts as vertices of a directed graph. A pair x - y means that artifact x can be followed by artifact y when constructing a spell. A spell is simply a directed path containing at least two different vertices.
codeforces competitive-programming Aug 6, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565J - Statue

We have a city represented as a weighted graph. Every house is a vertex with a fixed coordinate, and every road is an edge whose weight is the number of people travelling on that road. We need to choose an integer point for a statue.
codeforces competitive-programming Aug 5, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565H - Shopping Bags

The bags form a rooted forest. If bag i has b[i] = j, then i is a direct child of bag j. A bag can contain several other bags, and a bag with b[i] = 0 is a root of one of the trees.
codeforces competitive-programming Aug 5, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565G - Puppetteer

We have a rooted tree. Every vertex owns a unique number between 1 and N, so the numbers form a permutation of the vertices. For every vertex v, we look only at the vertices inside v's subtree and collect their numbers. These numbers create several maximal consecutive ranges.
codeforces competitive-programming Aug 5, 2026
Practice › Codeforces Solutions › AGM 2020, Final Round, Day 2 ›

CF 102565D - Galleries

We have a connected undirected graph representing the museum. Each vertex is a gallery and has a value. A visitor starts from a chosen gallery and can move only along corridors. The price of the ticket is the maximum value among all galleries visited during the walk.
codeforces competitive-programming Aug 5, 2026