删除有序数组中的重复项II

双指针标记

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        if(nums.size()<=2)
        return nums.size();
        int start=0,second=1,count=2;
        for(int i=2;i<nums.size();i++)
        {
            if(nums[i]!=nums[start])
            {
                nums[second+1]= nums[i];
                start++;
                second++;
                count++;
            }
        }
        return count;
    }
};