You are given an input string, s, and a pattern string, p. Your task is to implement regular expression matching between s and p, where the pattern may include the special characters '.' and '*':

• '.' matches any single character.

• '*' matches zero or more occurrences of the preceding character.

The match must cover the entire input string, not just part of it.

Constraints:

• $1 \leq$ s.length $\leq 20$

• $1 \leq$ p.length $\leq 20$

• s contains only lowercase English letters.

• p contains only lowercase English letters, '.', and '*'.

• It is guaranteed that for each appearance of the character '*', there will be a previous valid character to match.

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.