Similar to the question [Could a Turing Machine simulate a quantum computer?](https://quantumcomputing.stackexchange.com/questions/1/could-a-turing-machine-simulate-a-quantum-computer): given a 'classical' algorithm, is it always possible to formulate an equivalent algorithm which can be performed on a quantum computer? If yes, is there some kind of procedure we can follow for this? The resulting algorithm will probably not take full advantage of the possibilities of quantum computing, it's more of a theoretical question.