Remove Duplicates from Sorted Array II

Remove Duplicates from Sorted Array II

Follow up for "Remove Duplicates":
What if duplicates are allowed at most twice?

For example,
Given sorted array nums = [1,1,1,2,2,3],

Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3. It doesn't matter what you leave beyond the new length.

discuass的讲解：

https://discuss.leetcode.com/topic/7673/share-my-o-n-time-and-o-1-solution-when-duplicates-are-allowed-at-most-k-times

https://discuss.leetcode.com/topic/17180/3-6-easy-lines-c-java-python-ruby

提示上采用双指针。

更简洁的：判断nums[i]>nums[i-2]?与否