LeetCode OJ：Remove Duplicates from Sorted Array II（移除数组中的重复元素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.

典型的双指针问题，维护两个指针不断更新就可以了，代码如下：

 class Solution {
 public:
     int removeDuplicates(vector<int>& nums) {
         int sz = nums.size();
         if(!sz) return ;
         int start = ;//第二个指针
         int i = ;//第一个指针
         int count = ;
         int key = nums[];
         for(; i < sz; ++i){
             if(nums[i] == key)
                 count++;
             else{
                 for(int k = ; k < min(, count); ++k)
                     nums[start++] = key;//更改数组元素，指针前移
                 key = nums[i];
                 count = ;
             }
         }
         for(int k = ; k < min(, count); ++k)
             nums[start++] = key;
         return start;
     }
 };