leetcode

0540.cpp (426B)

 class Solution {
   public:
     int singleNonDuplicate(vector<int> &nums) {
         int low = 0, high = nums.size() - 1;
         while (low < high) {
             int mid = low + (high - low) / 2;
             if ((mid % 2 == 0 && nums[mid] == nums[mid + 1]) || (mid % 2 == 1 && nums[mid] == nums[mid - 1]))
                 low = mid + 1;
             else
                 high = mid;
         }
         return nums[low];
     }
 };