Remove Duplicates from Sorted Array II

<-M 80> Remove Duplicates from Sorted Array II

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        if(nums.size() <= 2)
            return nums.size();
        int index = 2;
        for(int i = 2; i < nums.size(); i++) {
            if(nums[i] != nums[index - 2])
                nums[index++] = nums[i];
        }
        return index;
    }
};