540. Single Element in a Sorted Array
python
class Solution:
def singleNonDuplicate(self, nums: List[int]) -> int:
l,r=0,len(nums)-1
while l<r:
mid=(l+r)//2
if mid%2==1 and nums[mid-1]==nums[mid]:
l=mid+1
elif mid%2==0 and nums[mid+1]==nums[mid]:
l=mid+1
else:
r=mid
return nums[l]二分