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Advanced3 qubitspar 4

Gate golf: move half a Bell pair

The two pre-placed gates entangle q0 with q1. Hand q1's half of the pair to q2, so that half the shots read |000⟩ and half |101⟩ with q1 left clean at |0⟩ — keeping the two starting gates. Par is 4 total, which means TWO added gates. The routing challenge did this with a three-CNOT SWAP for five; the point of this hole is that a full SWAP is more than the job needs. As always, the grader only sees the final state — rebuilding the pair from scratch on q0 and q2 also lands on the target, but then you have practised nothing.

Stuck on the concept? Read Entanglement.

Target
What you are aiming at100 %
|000⟩
|001⟩
|010⟩
|011⟩
|100⟩
|101⟩
|110⟩
|111⟩
Your circuit
What you are producing right now100 %
|000⟩
|001⟩
|010⟩
|011⟩
|100⟩
|101⟩
|110⟩
|111⟩
Gates
Single qubit
Two qubit
Three qubit
Other

Select a gate to see what it does, then tap a wire — or Tab to a wire and press Enter — to place it.

Circuit
Gates
2
Par
4
Pick a gate from the palette to start building.
Practice more like this

Generate a fresh target state drill at this difficulty. Every generated puzzle is verified solvable by execution before you see it — the generator runs its own solution through the same simulator and grader that will judge yours.