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].

解法一：

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (n < 3) {
            return n;
        }
        
        int remove_cnt = 0;
        bool first_same = false;
        int j = 0;
        for (int i = 1; i < n; ++i) {
            while (A[j] == A[i] && i < n) {
                if (!first_same) {
                    A[++j] = A[i++];
                    first_same = true;
                } else {
                    ++i;
                    ++remove_cnt;
                }
            }
            if (A[i] != A[j]) {
               A[++j] = A[i];
               first_same = false;
            }
        }
        return n - remove_cnt;
    }
};

解法二：

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (n < 3) {
            return n;
        }
        bool first_same = false;
        bool has_delete = false;
        int i = 0, j = 1;
        for (; j < n;) {
            if (A[i] == A[j]) {
                if (!first_same) {
                    first_same = true;
                    if (has_delete) {
                       A[++i] = A[j++];
                    } else {
                        ++i;
                        ++j;
                    }
                } else {
                    ++j;
                    has_delete = true;
                }
            } else {
                if (has_delete) {
                  A[++i] = A[j++];
                } else {
                    ++i;
                    ++j;
                }
                first_same = false;
            }
        }
        return  i + 1;
    }
};