[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) {
        vector<int> Acopy(A,A+n);
         if(n<=2)
             return n;
        int res = n;
        int temp = A[0];
        int tempNum = 1;
        int j = 1;
        for(int i=1;i<n;i++){
            if(Acopy[i]==temp && tempNum<2){
                A[j++]=Acopy[i];
               tempNum++;
            }else if(Acopy[i]==temp && tempNum>=2){
             tempNum++;
             res--;
            }else if(Acopy[i]!=temp){
              temp = Acopy[i];
              tempNum = 1;
              A[j++]=Acopy[i];
            }
            
        
        }//end for
        return res;
    }
};

关键数组A中的前res个元素要变化成需要的结果。