Single Element in a Sorted Array

You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once. Return _the single element that appears only once_. Your solution must run in `O(log n)` time and `O(1)` space.   **Example 1:** **Input:** nums = [1,1,2,3,3,4,4,8,8] **Output:** 2 ``` **Example 2:** **Input:** nums = [3,3,7,7,10,11,11] **Output:** 10 ```   **Constraints:** - `1 <= nums.length <= 105` - `0 <= nums[i] <= 105`