LeetCode 80. Remove Duplicates from Sorted Array II

Follow up for "Remove Duplicates":
What if duplicates are allowed at most twice?

For example,
Given sorted array nums = [1,1,1,2,2,3],

Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3. It doesn't matter what you leave beyond the new length.

class Solution {public:    int removeDuplicates(vector<int>& nums) {        if(nums.size()==0) return 0;        int l=1,cnt=1;;        vector<int>v(nums.size());        v[0]=nums[0];        for(int i=1;i<nums.size();i++){            if(nums[i]==nums[i-1]){                cnt++;            }            else{                cnt=1;            }            if(cnt<=2){                v[l++]=nums[i];            }        }        for(int i=0;i<l;i++){            nums[i]=v[i];        }        return l;    }};