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.

水题，不要用vector.erase()方法， 直接删除操作vector内部会遍历后边元素， 所以时间花费较大， 用一个临时数组，保存一下就OK了

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        vector<int> res;
        for(int i=0, s = 0; i<nums.size(); ++ i)
        {
            if(i == 0 || nums[i] != nums[i-1])
                s = 0;
            else
                s ++;

            if(s >= 2)
                continue;

            res.push_back(nums[i]);
        }
        nums.clear();
        nums = res;
        return int(nums.size());
    }
};