说明：  对已经排序过的、具有n个元素的数组A，检索是否存在元素x。当n是奇数时，用二叉检索算法检索；当n是偶数时，用线性检索算法检索。写出算法分析和时间复杂度。
(Already sorted array of n elements A, retrieves whether there exists an element x. When n is odd, using the binary search algorithm to retrieve when n is even, the linear search algorithm to retrieve. Write the algorithm and time complexity.)