【leetcode】【26】Remove Duplicates from Sorted Array

一、问题描述

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.

Do not allocate extra space for another array, you must do this in place with constant memory.

For example,

Given input array nums = 

[1,1,2]

,

Your function should return length = 

2

, with the first two elements of nums being 

1

 and 

2

 respectively.
It doesn't matter what you leave beyond the new length.

二、问题分析

还是一位数组的遍历问题。首先数组已排序，题目说明了最终的数组前半部分是有序且无重复元素的，后半部分不用管，这就提示我们可以把后边的无重复元素覆盖到前边，至于覆盖的位置需要一个索引来计数。

三、Java AC代码

public int removeDuplicates(int[] nums) {
if(nums.length==0 || nums==null) return 0;
int ans = 0;
for(int i = 1;i<nums.length;i++){
if(nums[i]!=nums[ans]){
if(++ans!=i)
nums[ans] = nums[i];
}
}
return ans+1;
}