540. Single Element in a Sorted Array (Medium) - TengnanYao/daily_leetcode GitHub Wiki

class Solution:
    def singleNonDuplicate(self, nums: List[int]) -> int:
        l, r = 0, len(nums) - 1
        while l <= r:
            m = (l + r) // 2
            if m % 2 == 1:
                if nums[m] == nums[m - 1]:
                    l = m + 1
                else:
                    r = m - 1
            else:
                if nums[m] == nums[m - 1]:
                    r = m - 1
                else:
                    l = m + 1
        return nums[l - 1]