Bad Qubits — Learn Quantum by Doing

|q⟩ Bad Qubits

Multiple choice

In the Deutsch-Jozsa algorithm, after the final layer of Hadamards you measure the n input qubits. How is the result interpreted?

The outcome is random, so you must repeat the circuit many times to decide
All-zeros outcome means f is balanced; any other outcome means f is constant
All-ones outcome means f is constant; all-zeros means f is balanced
All-zeros outcome means f is constant; any other outcome means f is balanced