问题4：你能根据这个描述写出随机算法的图灵机模 型吗？ If one wants to formalize the notion of randomized algorithms,then one can take deterministic Turing machines A with an infinite additional tape.This additional tape is read-only;it contains an infinite random sequence of 0s and 1s,and A may move on it only from the left to the right.Another possibility is to take a nondeterministic Turing machine with nondeterministic guesses over at most two possibilities and to assign the probability to every such possibility.问题4：你能根据这个描述写出随机算法的图灵机模 型吗？