This quantum circuit performs binary addition of two input bits, producing a sum and carry bit.
```python
from qiskit import QuantumCircuit
# Create a quantum circuit with 5 qubits and 2 classical bits
qc = QuantumCircuit(5, 2)
# Initialize input bits A=1, B=1, Cin=0
qc.x(0) # Set qubit 0 to |1⟩ (A=1)
qc.x(1) # Set qubit 1 to |1⟩ (B=1)
# Qubit 2 is already |0⟩ (Cin=0)
# Quantum full adder circuit
# Compute the sum S = A ⊕ B ⊕ Cin
qc.cx(0, 3) # S ^= A
qc.cx(1, 3) # S ^= B
qc.cx(2, 3) # S ^= Cin
# Compute the carry-out Cout
qc.ccx(0, 1, 4) # If A and B then Cout
qc.ccx(0, 2, 4) # If A and Cin then Cout
qc.ccx(1, 2, 4) # If B and Cin then Cout
# Measure the sum and carry-out
qc.measure(3, 0) # Measure sum into classical bit 0
qc.measure(4, 1) # Measure carry-out into classical bit 1
```'Failed to run program: \'409 Client Error: Conflict for url: https://api.quantum.ibm.com/runtime/jobs. {"errors":[{"message":"You have reached the limit of 3 pending jobs. Please wait for a job to complete or cancel one before submitting anything new.","code":3458,"solution":"Wait until some previous jobs were finished. You can cancel pending jobs to run new jobs.","more_info":"https://docs.quantum-computing.ibm.com/errors"}]}\''