LeetCode OJ 80 Remove Duplicates from Sorted ArrayII

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：重复数可以达到两个，则在OJ26的基础上加一个flag标记重复数字即可

代码如下

class Solution {
public:
int removeDuplicates(vector<int>& nums)
{
int length = nums.size();
if(length<=2)
return length;
int index = 0;
int flag=0;
for(int i=1;i<length;i++)
{
if(nums[index]==nums[i])
{

if(flag==0)//flag标记重复数的次数，当为0次时表示可以增加一个重复数
{

nums[++index]=nums[i];
flag++;
}
else//达到重复上限
{
flag++;
}
}
else
{
flag=0;
nums[++index]=nums[i];
}
}
return index+1;
}
};

运行时间：20ms