adding general grover example

using GroverPhaseOracle = KernelSignature<qreg>;

__qpu__ void reflect_about_uniform(qreg q) {

  compute {

    H(q);

    X(q);

  } action {

    std::vector<qubit> ctrl_qubits;

    for (int i = 0; i < q.size() - 1; i++) {

      std::cout << "adding qubit " << q[i].second << "\n";

      ctrl_qubits.push_back(q[i]);

    }

    auto last_qubit = q[2];

    Z::ctrl(ctrl_qubits, last_qubit);

  }

  return;

}

__qpu__ void run_grover(qreg q, GroverPhaseOracle oracle,

                        const int iterations) {

  H(q);

  for (int i = 0; i < iterations; i++) {

    oracle(q);

    reflect_about_uniform(q);

  }

  Measure(q);

}

__qpu__ void oracle(qreg q) {

    CZ(q[0], q[2]);

    CZ(q[1], q[2]);

}

__qpu__ void ccz(qreg q) {

    Z::ctrl({q[0], q[1]}, q[2]);

}

int main() {

    auto q = qalloc(3);

    run_grover(q, oracle, 1);

    q.print();

    run_grover::print_kernel(q, oracle, 1);

    auto m = ccz::as_unitary_matrix(q);

    std::cout << m << "\n";

    std::cout << run_grover::openqasm(q, oracle, 1) << "\n";

}

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