Given a string s representing a mathematical expression, evaluate and return its result as an integer.

The expression string contains digits, addition '+', subtraction '-', multiplication '*', division '/', and parentheses '(' and ')'.

Note: The integer division should truncate toward $0$.

Constraints:

• $1 \leq$ s.length $\leq 10^4$

• s consists of digits, '+', '-', '*', '/', '(', and ')'.

• s is a valid expression.

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.