Flip the CNOT

The cross-resonance coupler on this chip only drives CX with qubit 0 as control. Your algorithm needs the opposite direction.

Objective

Return a two-qubit circuit equal to CX with control q1 and target q0.

Constraints

• Allowed gates: h, cx.
• Every CX must have control 0 and target 1.

Entry Point

Checks

• Exports build_reversed_cnot().
• Only uses CX(0, 1) and H.
• The unitary equals CX(1, 0).