The following function is a recursive version of the binary search:以下函数是二分查找的递归版：
For a vector of size n, the time and space complexity of the recursive version and the iterated version learned in class are: 对于规模为n的向量，该递归版的时间、空间复杂度和课堂上所学的迭代版的时间、空间复杂度分别是：
AO(n),O(nlog2(n)),O(n),O(1)
B，O(nlog2(n)),O(nlog2(n)),O(nlog2(n))，O(nlog2(n))
CO(log2(n)),O(1),O(log2(n)),O(1)
DO(log2(n)),O(log2(n)),O(log2(n)),O(1)