Remove Duplicates from Sorted Array II

Given a sorted integer array nums, remove duplicates in-place such that each unique element appears at most twice. Return k — the count of remaining elements.

The first k elements of nums must hold the result. Beyond index k, values don't matter.

Example 1:

Input:  nums = [1,1,1,2,2,3]
Output: k = 5, nums = [1,1,2,2,3,_]

Example 2:

Input:  nums = [0,0,1,1,1,1,2,3,3]
Output: k = 7, nums = [0,0,1,1,2,3,3,_,_]

Constraints:

• 1 <= nums.length <= 3 × 10⁴
• -10⁴ <= nums[i] <= 10⁴
• nums is sorted in non-decreasing order