Implement a quantum oracle on 3 qubits which implements a majority function. Majority function on 3-bit vectors is defined as follows: $$f(\vec{x}) = 1$$ if vector $$\overrightarrow{\tau}$$ has two or three 1s, and 0 if it has zero or one 1s.

For an explanation on how this type of quantum oracles works, see Introduction to quantum oracles.

You have to implement an operation which takes the following inputs:

• an array of 3 qubits x in arbitrary state (input register),
• a qubit y in arbitrary state (output qubit).

The operation doesn't have an output; its "output" is the state in which it leaves the qubits.

Your code should have the following signature:

见题面 Input 部分

见题面 Output 部分