Given a sorted array consisting of only integers where every element appears twice except for one element which appears once. Find this single element that appears only once.

Example 1:

Input:[1,1,2,3,3,4,4,8,8]Output:2

Example 2:

Input:[3,3,7,7,10,11,11]Output:10

Note:Your solution should run in O(log n) time and O(1) space.

ANSWER:

class Solution {
public:    
    int singleNonDuplicate(vector& nums) {              
          vector::iterator i;
          int answer = 0;
          for (i = nums.begin(); i != nums.end() ; i++)
           {
              answer = answer ^ *i;
          }
          return answer;
    }
};

for (int i = 0; i < nums.capaity; i++) {
              answer = answer ^ nums.at(i);
}