remove duplicates from sorted array 2

code

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        int n = nums.size();
        if(n <= 2)
        {
            return n;
        }

        int prev = 1;
        for(int i = 2; i<n; i++)
        {
            if(nums[i] != nums[prev] || nums[i] != nums[prev-1])
            {
                nums[++prev] = nums[i];
            }

        }

        return prev+1;

    }
};