Multiple choice
For this circuit, what is the probability that measuring all 3 qubits yields exactly |111⟩ (qubit 0 leftmost)?
const c = circuit(3); c.h(0); c.h(1); c.h(2); // Oracle: phase-flip |000> c.x(0); c.x(1); c.x(2); c.h(2); c.ccx(0, 1, 2); c.h(2); c.x(0); c.x(1); c.x(2); // Oracle: phase-flip |111> c.h(2); c.ccx(0, 1, 2); c.h(2); // Diffuser c.h(0); c.h(1); c.h(2); c.x(0); c.x(1); c.x(2); c.h(2); c.ccx(0, 1, 2); c.h(2); c.x(0); c.x(1); c.x(2); c.h(0); c.h(1); c.h(2); return c;
Commit your prediction for P(|111⟩) — then run it.