Grover With a Sealed Oracle

Search 8 items with a phase oracle you are not allowed to open. Two Grover iterations is the sweet spot for N = 8, and your diffuser has to be built by hand.

Objective

build_grover_circuit(oracle) receives a 3-qubit phase-oracle Gate that flips the sign of one unknown basis state. Return a 3-qubit circuit with exactly two oracle calls that measures the marked state with probability above 0.94.

Constraints

• Exactly two qc.append(oracle, [0, 1, 2]) calls.
• No GroverOperator / initialize shortcuts.
• Do not inspect the oracle: every non-oracle gate must be identical for every oracle.

Entry Point

Checks

• Exports build_grover_circuit(oracle).
• Calls the oracle exactly twice.
• Amplifies each of the 8 possible targets above 94%.
• The circuit is identical apart from the oracle box.