离散01串问题，(n,k)01 串定义为：长度为n 的01 串，其中不含k 个连续的相同子串。对于给定的正整数n 和k，计算(n,k)01 串的个数。-discrete series of 01 questions, and (n, k) 01 Series : the definition of the length of n strings of 01, which is non-consecutive k-the same string. For a given positive inte