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.
- 不需要的数时成对的，所以可以通过xor操作将他们置为0，最后的数就是结果
- 答案要求是时间复杂度为log n，由于是已经排序的数组那么，可以考虑使用二分查找，根据奇偶来判断在哪边查询