80. Remove Duplicates from Sorted Array II

problem：

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.
思路是只保存最后两个重复的元素，所以对nums进行循环，若和两位后的数据不一样，则保存下来，否者不操作。

class Solution {
public:
int removeDuplicates(vector<int>& nums) {
int result=0;
if(nums.size() < 3)
return nums.size();

vector<int> temp;
for(int i=0; i<nums.size()-2; i++)
{
if(nums[i] != nums[i+2])
{
temp.push_back(nums[i]);
result++;
}

}
temp.push_back(nums[nums.size()-2]);
temp.push_back(nums[nums.size()-1]);
nums = temp;
return result+2;
}
};