You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once. Find this single element that appears only once. Follow up: Your solution should 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 <= 10^5 0 <= nums[i] <= 10^5