*Remove Duplicates from Sorted Array II

题目：

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].

题解：

之前是不允许有重复的。

现在是可以最多允许2个一样的元素。

然后删除duplicate，返回长度。

删除duplicate的方法就是指针的操作。具体方法见代码。

   public int removeDuplicates(int[] nums) 

    {

        int n=nums.length;

        int prev=1;

        int curr=2;

        if (n<=2) return n;

        while(curr<n)

        {

            if(nums[curr]==nums[prev]&&nums[curr]==nums[prev-1]) curr++;

            else 

            {

                prev++;

                nums[prev]=nums[curr];

                curr++;

            }

            

        }

        return prev+1;

    }

Reference: http://www.programcreek.com/2013/01/leetcode-remove-duplicates-from-sorted-array-ii-java/