The 2025 ICPC South America - Brazil First Phase

13 problems from The 2025 ICPC South America - Brazil First Phase (contest 106073), difficulty -. 13/13 solutions verified against sample I/O.

13 items

The 2025 ICPC South America - Brazil First Phase

ICPC/IOI | 13 problems | 13/13 verified | Difficulty - | 12m 2s

#	Problem	Time	✓
A	A healthy menu	53s	✓
B	Baralho Alho	52s	✓
C	Collatz polynomial	55s	✓
D	Dominoes	55s	✓
E	Expansion of the road network	59s	✓
F	Frangolino ali na mesa	1m 16s	✓
G	Generating patterns	1m 16s	✓
H	How many teams?	49s	✓
I	Investigating Quadrad\u00f4meda	59s	✓
J	Jo\u00e3o Jo\u00e3o	41s	✓
K	Knockout, swiss and other kinds of tournaments	51s	✓
L	LLMs	45s	✓
M	Minas Gerais' walls	51s	✓

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CF 106073I - Investigating Quadradômeda

We are given a sequence of points in the plane, representing stars visited in a fixed order. Consecutive stars are always aligned either horizontally or vertically, so each move between star $i$ and star $i+1$ is a straight segment parallel to an axis.

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CF 106073A - A healthy menu

Each class reports how many students like each fruit, but this information is aggregated. For a fixed class and a fixed fruit, the value tells us how many distinct students in that class like that fruit.

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CF 106073L - LLMs

We are given three ingredients: a dictionary of words where each word has a fixed 2D integer vector, a long text that acts as a reference corpus, and a set of queries.

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CF 106073G - Generating patterns

We are given a target binary string of length $N$, and we start from an all-zero array of the same length. We are allowed to perform an operation that picks a starting position $i$ and XORs a fixed 8-bit pattern $B$ onto the array, aligned so that $B[j]$ affects position $i+j$…

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CF 106073D - Dominoes

We are given a small collection of domino tiles, each tile labeled with two numbers from 1 to 6. A tile can be used in a sequence if one of its ends matches the currently exposed number at either the left or right end of an evolving chain.

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CF 106073J - João João

We are given a fixed collection of 10 tasks, each labeled with a difficulty value from the set {1, 2, 3, 4}. The organizer wants to eventually be able to select a set of four tasks, one from each difficulty level.

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CF 106073E - Expansion of the road network

We are given the final state of an undirected simple graph on $N$ cities. We are told that this graph was not originally built in this form. Instead, it started as a tree on the same $N$ vertices.

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CF 106073M - Minas Gerais' walls

We are given a one-dimensional wall made of consecutive segments, each segment having an initial height. We are allowed to perform exactly one reinforcement operation.

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CF 106073H - How many teams?

Each student in this problem can be represented by a bitmask of length $K$, where the $j$-th bit indicates whether the student has a particular frontend skill.

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CF 106073C - Collatz polynomial

We are given a polynomial where every coefficient is either 0 or 1, so the polynomial is best thought of as a set of powers of x. If the coefficient of $x^k$ is 1, we include that term, otherwise we do not.

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CF 106073K - Knockout, swiss and other kinds of tournaments

We are asked to design a tournament population so that a very specific elimination system can run without ever getting stuck. Each player starts with zero wins and zero losses. A match always produces a winner and a loser.

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CF 106073F - Frangolino ali na mesa

We are given a sequence of commands processed by a robot that moves between restaurant tables and records orders. The robot starts at table 1.

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CF 106073B - Baralho Alho

We start with a deck of N positions. Each position initially holds a card with some value, and we are given a target arrangement describing what value we want at each position after repeated shuffles.