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.

 

题目大意：给定一个排好序的数组，有重复元素，要求返回新数组长度，新数组中重复元素只能出现两次，新长度后面的是什么无所谓。

解题思路，从前向后遍历，记录一个newLen变量，重复元素记录两次，非重复元素就直接copy到新数组应有的下标处。

    public int removeDuplicates(int[] nums) {
        if(nums==null||nums.length==0){
            return 0;
        }
        int newLen=0;
        for(int i=0;i<nums.length;i++){
            int pos=i;
            nums[newLen++]=nums[i];
            while(i<nums.length-1&&nums[i]==nums[i+1]){
                i++;
            }
            if(pos==i)
                continue;
            nums[newLen++]=nums[i];
        }
        return newLen;
    }