Remove Duplicates from Sorted Array II leetcode java

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。

代码如下：

 1     public int removeDuplicates(int[] A) {
 2         if (A.length <= 2)
 3             return A.length;
 4  
 5         int prev = 1; // point to previous
 6         int curr = 2; // point to current
 7  
 8         while (curr < A.length) {
 9             if (A[curr] == A[prev] && A[curr] == A[prev - 1]) {
10                 curr++;
11             } else {
12                 prev++;
13                 A[prev] = A[curr];
14                 curr++;
15             }
16         }
17  
18         return prev + 1;
19     }

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