Remove Duplicates from Sorted Array II

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].

先排序，然后有三种允许的情况可以添加。

public class Solution {
    public int removeDuplicates(int[] A) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        Arrays.sort(A);
        int Len = 0;
        for (int i = 0; i < A.length; i++)
            if (i == 0 || A[i - 1] != A[i] || ( i != 0 && A[i] == A[i - 1] && (Len < 2 || A[Len - 1] != A[Len - 2])) )
                A[Len ++] = A[i];
        return Len;
    }
}

 第三遍：

public class Solution {
    public int removeDuplicates(int[] A) {
        if(A.length < 3) return A.length;
        int cur = 2;
        for(int i = 2; i < A.length; i ++){
            if(A[i] != A[cur - 2]) A[cur ++] = A[i];
        }
        return cur;
    }
}