Leetcode: Remove Duplicates from Sorted Array II

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        auto C = A;
        int len = 0;
        
        for (int i = 0 ; i < n ; ++i) {
            if (len >= 2 && C[len-1] == C[len-2] && A[i] == C[len-1]) continue;
            C[len++] = A[i];
        }
        return len;
    }
};