Remove Duplicates from Sorted Array II

Problem

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

For example,
Given sorted array A = [1,1,1,2,2,3],
Your function should return length = 5, and A is now [1,1,2,2,3].

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Idea

The idea is the same as Remove Duplicates from Sorted Array. We just use one parameter to record how many duplicates have happen.

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Solution