https://leetcode.com/problems/remove-duplicates-from-sorted-array/

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.

 

思路：

也是指针思想，利用新array任意元素一定不会比旧array该元素所在对应位置index大的原理（也可以看作栈），通过两个指针表征新旧array。

遍历一遍array，只有当遇到新元素时，压入新array。

 

AC代码：

 1 class Solution {
 2 public:
 3     int removeDuplicates(vector<int>& nums) {
 4         if(nums.size()==0)
 5             return 0;
 6         int p=0,n=nums.size();
 7         for(int i=1;i<n;i++){
 8             if (nums[i]!=nums[p]){
 9                 nums[++p]=nums[i];
10             }
11         }
12         return p+1;
13     }
14 };