【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 i, j, k = 1;
        for (i = 0, j = 1; j < n; ++j) {
            if (A[i] != A[j]) {
                A[++i] = A[j];
                k = 1;
            } else if (k == 1) {
                A[++i] = A[j];
                ++k;
            }
        }
        return i + 1;
    }
};

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        if (n <= 2) return n;
        int i, j;
        for (i = 1, j = 2; j < n; ++j) {
            if (A[j] != A[i - 1]) {
                A[++i] = A[j];
            }
        }
        return i + 1;
    }
};