Marking a specific quantum state in the oracle function in the Grover's algorithm

Question

I have a simple implementation of Grover's algorithm. As depicted in the results below, the oracle function marks the state |111>. How can I change the Oracle function to mark |010>?

    import cirq
    from cirq import H, Z, X
    
    qq = cirq.LineQubit.range(3)
    circuit = cirq.Circuit()
    circuit.append(H.on_each(*qq))
    
    def oracle():
        yield Z(qq[2]).controlled_by(*(qq[0:2]))
    
    def grover_diffusion():
        yield H.on_each(*qq)
        yield X.on_each(*qq)
        yield Z(qq[2]).controlled_by(*(qq[0:2]))
        yield X.on_each(*qq)
        yield H.on_each(*qq)
    
    for i in range(2):
        circuit.append(oracle())
        circuit.append(grover_diffusion())
    
    circuit.append(cirq.measure(*qq, key='result'))
        
    # determine the statistics of the measurements
    s = cirq.Simulator() 
    trials_number = 1000
    samples = s.run(circuit, repetitions=trials_number)
    
    def bitstring(bits):
        return "".join(str(int(b)) for b in bits)
    
    counts = samples.histogram(key = "result", fold_func = bitstring)
    
    print("Measurement output: ", counts)
    # Output is something like 
    # Measurement output:  Counter({'111': 953, '001': 10, '000': 9, '110': 9, '010': 9, '101': 4, '100': 4, '011': 2})
```

Answer 1

def oracle():
    yield X(qq[0])
    yield X(qq[2])
    yield Z(qq[2]).controlled_by(*(qq[0:2]))
    yield X(qq[0])
    yield X(qq[2])

For a general Grover oracle to find a specific 3-qubit computational basis state, flanking the CCZ with $X$ gates on the qubits that need to be zero will work. A CCZ only causes the phase to be reversed if all 3 qubits are 1 (for the CCZ gate there's no actual difference between control and target unlike CCX, so it doesn't matter which one of the three that the Z gate is applied to). By doing the $X$ on a qubit before that causes the phase reverse to occur if that input is 0 instead, and the $X$s after the CCZ return the relevant qubits back to 0 while keeping the phase reversal if it occurred.