*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/