Given the head of a singly linked list, reverse the linked list and return its updated head.

Constraints:

Let n be the number of nodes in a linked list.

• $1 \leq$ n $\leq 500$
• $-5000 \leq$ Node.value $\leq 5000$

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.