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

給定一個有序數組，返回數組中無重復數字的個數

C++（32ms）：

 1 class Solution {
 2 public:
 3     int removeDuplicates(vector<int>& nums) {
 4         int res = 1 ;
 5         int len = nums.size() ;
 6         if (len < 1)
 
 7             return 0 ;
 8         for (int i = 0 ; i< len-1 ; i++){
 9             if (nums[i] != nums[i+1]){
10                 nums[res] = nums[i+1] ;
11                 res++ ;
12             }
13         }
14         return res ;
15     }
16 };

26. Remove Duplicates from Sorted Array