QCoder

Problem Statement

You are given an integer $n$ . Implement the oracle $O$ on a quantum circuit $\mathrm{qc}$ consisting of an $n$ -qubit register $\mathbf{x}$ and a $1$ -qubit register $y$ , and acting on the computational basis states as

\ket{\mathbf{x}}\ket{y} \xrightarrow{O} \ket{\mathbf{x}}\ket{y \oplus x_1 \oplus x_2 \oplus ... \oplus x_n}

Here, $x_i$ denotes the $i$ -th qubit of $\mathbf{x}$ .

Constraints

$1 \leq n \leq 10$
Global phase is ignored in judge.
The submitted code must follow the specified format:

from qiskit import QuantumCircuit, QuantumRegister
 
 
def solve(n: int) -> QuantumCircuit:
    x, y = QuantumRegister(n), QuantumRegister(1)
    qc = QuantumCircuit(x, y)
    # Write your code here:
 
    return qc

Sample Input

$\ket{\mathbf{x}}\ket{y} = \frac{1}{\sqrt{2}} (\ket{101} + \ket{010})$ : The implemented oracle $O$ should perform the following transformation.

\ket{\mathbf{x}}\ket{y} = \frac{1}{\sqrt{2}} (\ket{101} + \ket{010}) \xrightarrow{O} \frac{1}{\sqrt{2}} (\ket{100} + \ket{011})

Hints

Open

You can get the number of qubits $n$ in $\mathbf{x}$ as follows:

n = len(x)

You can apply the quantum gate $g$ to the $i$ -th qubit of $\mathbf{x}$ as follows:

qc.g(x[i - 1])

B2: XOR Oracle

Problem Statement

Constraints

Sample Input

Hints