本質上這兩道題用的是同一種方法。設定一個temp下標表示更新過的陣列元素下標，若符合題目要求，則將元素賦值給temp當前所在位置。最後返回temp。

26. Remove Duplicates from Sorted Array

Given a sorted array nums, 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 by modifying the input array in-place with O(1) extra memory.

實現程式碼：（C++）

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        if(nums.size()<=1)
            return nums.size();
        int temp = 1;
        
        for(int i=1; i<nums.size(); i++){
            if(nums[i]!=nums[i-1]){
                nums[temp] = nums[i];
                temp++;
            }
        }
        
        return temp;
    }
};
 

27. Remove Element

Given an array nums and a value val, remove all instances of that value in-place and return the new length.
Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
The order of elements can be changed. It doesn’t matter what you leave beyond the new length.

實現程式碼：（C++）

class Solution {
public:
    int removeElement(vector<int>& nums, int val) {
        int temp = 0;
        for(int i=0; i<nums.size(); i++){
            if(nums[i]!=val){
                nums[temp] = nums[i];
                temp++;
            }
        }
        return temp;
    }
};