You are given an integer array nums that originally contained all the numbers from $1$ to n, where n is the length of nums. Due to an error, one number in the collection was duplicated, causing another number to be missing.

Find the number that occurs twice and the number that is missing, and return them as an array in the format [duplicate, missing].

Constraints:

• $2 \leq$ nums.length $\leq 10^4$

• $1 \leq$ nums[i] $\leq 10^4$

Now, let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Implement your solution in the following coding playground.