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;
}
};