 # Find All Disappeared Numbers in an Array Lab

Easy
3
52.9% Acceptance

In this lab, you will be tasked with finding all the disappeared numbers in an array. The array `nums` will contain `n` integers where each number, `nums[i]`, is in the range `[1, n]`. Your task is to return an array of all the integers within the range `[1, n]` that do not appear in `nums`. Use the ESM (ECMAScript Module) import/export for this lab.

## Lab Description

Given an array `nums` of `n` integers where `nums[i]` is in the range `[1, n]`, return an array of all the integers in the range `[1, n]` that do not appear in `nums`.

Example 1:

Input: `nums = [4,3,2,7,8,2,3,1]` Output: `[5,6]`

Example 2:

Input: `nums = [1,1]` Output: ``

Example 3:

Input: `nums = [2,2,3,4,5,6,7,8]` Output: ``

### Constraints:

• `n == nums.length`
• `1 <= n <= 105`
• `1 <= nums[i] <= n`

Follow up: Could you do it without extra space and in `O(n)` runtime? You may assume the returned list does not count as extra space.

## Challenges

1. Implement the `findDisappearedNumbers` function that takes in an array `nums` and returns an array of missing numbers.
2. The function should not use extra space and should have a runtime of `O(n)`.