Leetcode_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 start=0,cur=1;        int cnt=0;        while(cur<=n-1){            if(A[start]==A[cur]){                cnt++;                if(cnt>1){                    cur++;                }                else{                    A[++start]=A[cur++];                }            }            else{                cnt=0;                 A[++start]=A[cur++];            }        }        return start+1;    }};