LC 0540 [M] Single Element in a Sorted Array - ALawliet/algorithms GitHub Wiki

first binary search with modified m and l

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:
                m -= 1 # should be at even index

            if nums[m] == nums[m+1]:
                l = m + 2 # yes pair, single must be on right, +1 to skip dupe
            else:
                r = m # no pair, single must be on left

        return nums[l]