leetcode[80]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].

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        if(n<=2)return n;
        int len=1;
        int curr=A[0];
        map<int,int> Amap;
        Amap[curr]=1;
        for(int i=1;i<n;i++)
        {
            if(A[i]==curr)
            {
                Amap[curr]++;
                if(Amap[curr]<=2)
                {
                    A[len]=curr;
                    len++;
                }
            }
            else
            {
                curr=A[i];
                Amap[curr]=1;
                A[len]=curr;
                len++;
            }
        }
        return len;
    }
};