模拟题，但是做起来好费劲啊。
一次AC:

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        if(n == 0)
            return n;
        int now;
        int count = 0;
        int len = n;
        for(int i = 0;i < len;i++)
        {
            if(count == 0 || now != A[i])
            {
                count = 1;
                now = A[i];
                continue;
            }
            if(A[i] == now)
            {
                if(count == 2)
                {<br />
                    int dis = 0;
                    int tmp = A[i];
                    for(int j = i+1;j &lt; len;j++)
                    {
                        if(tmp == A[j])
                        {
                            dis++;
                        }
                        else
                        {
                            A[j-1-dis] = A[j];
                        }
                    }
                    len-=1+dis;
                    i--;
                }<br />
                else
                    count++;
            }
        }
        return len;
    }
};