540. Single Element in a Sorted Array

You are given a sorted array consisting of only integers where every element appears exactly twice, except for one element which appears exactly once. Find this single element that appears only once.

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

Example 1:

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

Example 2:

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

Constraints:

• 1 <= nums.length <= 10^5
• 0 <= nums[i] <= 10^5

# @lc code=start
using LeetCode

function single_non_duplicate(nums::Vector{Int})
    i, j = 1, length(nums)
    while i < j
        mid = (i + j) >> 1
        if isodd(mid)
            nums[mid] == nums[mid + 1] ? (i = mid + 2) : (j = mid)
        else
            nums[mid] == nums[mid + 1] ? (j = mid - 1) : (i = mid + 1)
        end
    end
    return nums[i]
end
# @lc code=end

single_non_duplicate (generic function with 1 method)

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