Remove Duplicates from Sorted Array II

Leetcode

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.

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Analysis

Ref1
和之前的remove duplicates from sorted array I思路一样。用两指针，第一个指针i遍历整个数组，第二个指针index用来存不超过三次的数

Code

public class Solution {
    public int removeDuplicates(int[] nums) {
        if(nums.length<=2) {return nums.length;}
        int index = 1;
        for (int i=2; i<nums.length; i++){
            //IMPORTANT! Check duplicates around nums[index], not nums[i]
            if(nums[i]!=nums[index] || nums[i]!=nums[index-1]){
                index++;
                nums[index]=nums[i];
            }
        }
        return index+1;
    }
}