SBC Brazilian Phase Zero 2025

13 problems from SBC Brazilian Phase Zero 2025 (contest 105925), difficulty -. 13/13 solutions verified against sample I/O.

13 items

SBC Brazilian Phase Zero 2025

Special | 13 problems | 13/13 verified | Difficulty - | 12m 21s

#	Problem	Time	✓
A	Ambiguous Schr\u00f6dinger Cat	47s	✓
B	Periodic Search	54s	✓
C	Matrix Logic Circuits	1m 3s	✓
D	Quantum Decoherence	48s	✓
E	Particle Energization	1m 11s	✓
F	Feynman Memorizing Numbers	45s	✓
G	Grover and His Special Paths	1m 5s	✓
H	Binary Palindromic Harmony	46s	✓
I	Inspecting the Entanglement	53s	✓
J	Journey of the Particles	1m 3s	✓
K	K Missing Elements	1m 25s	✓
L	qPhones Production Line	40s	✓
M	Spooky Movement at a Distance	1m 1s	✓

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925K - K Missing Elements

We are given a sequence that defines an ordering constraint between positions and another sequence that assigns a weight to each position.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925E - Particle Energization

A particle starts at position 1 on an infinite number line. A fixed parameter $Y$ is given. The particle evolves in discrete steps.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925C - Matrix Logic Circuits

We are given a quantum circuit described as a sequence of reversible logic gates acting on an N-qubit system. Each gate is either a CNOT or a CCNOT.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925J - Journey of the Particles

We are given a circular arrangement of N filters. Each filter has a threshold value, and particles move through these filters in a fixed direction. A particle starts at filter i with an initial phase equal to the threshold of that filter.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925M - Spooky Movement at a Distance

We are given an array of integers placed on positions from 1 to N. A “path” is formed by picking any starting position and then repeatedly either stopping or jumping to a strictly larger index.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925L - qPhones Production Line

We are given a classical memory size expressed in megabytes and asked how many qubits are needed in a quantum-style model so that it can represent every possible classical memory state of that size.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925G - Grover and His Special Paths

We are given a tree where each vertex must be assigned a value from 1 to 5. The number of vertices assigned each value is fixed in advance, so exactly cnt1 vertices must get value 1, exactly cnt2 vertices must get value 2, and so on up to 5.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925H - Binary Palindromic Harmony

We are given a single integer $X$. We need to find the largest integer $Y$ such that $Y le X$ and the binary representation of $Y$ is a palindrome.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925B - Periodic Search

We are given a rooted tree where each node represents a state of a system, and each edge from a parent to a child is labeled with a lowercase letter.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925D - Quantum Decoherence

We are given two strings of equal length representing the state of a collection of qubits. The first string describes an “isolated” configuration, where some positions are stable bits 0 or 1, and some positions are uncertain and marked as , meaning the qubit is in…

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925I - Inspecting the Entanglement

We are given a time interval of length $T$, and at every second exactly one sensor must be active. Each sensor produces a value that depends on both the sensor and the time, so activating sensor $i$ at time $j$ contributes $c(i, j)$ to the total score.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925F - Feynman Memorizing Numbers

We are given a static array of up to a thousand integers, and multiple independent queries. Each query asks for the number of distinct quadruples of indices $(i, j, k, l)$ with strictly increasing order such that the sum of the four corresponding values equals the query target.

Practice › Codeforces Solutions › SBC Brazilian Phase Zero 2025 ›

CF 105925A - Ambiguous Schrödinger Cat

We are given a system with two binary pieces of information: whether a box is open or closed, and the actual internal state of a cat inside it. The first value, C, describes observability. If the box is closed, the state of the cat cannot be observed externally.