Remove Duplicates from Sorted Array II

原题：

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].

public int removeDuplicates(int[] A) {
		if(A.length <= 2) {
			return A.length;
		}
		
		int index = 1;
		for(int i=2; i<A.length; i++) {
			if(A[i]!=A[index] || A[i]!=A[index-1]) {
				A[++index] = A[i];
			}
		}
		
		return index+1;
    }