Learn and practice the In-place Reversal of a Linked List, Stacks, and Matrices patterns to solve coding interview problems.

Educative-99 in Python: Accelerate Your Coding Interview Prep

Interviewers want to be sure that the candidate is comfortable manipulating linked lists, arrays, and data structures based on them, such as stacks and matrices. This module will provide the practice you need to review the concepts and techniques needed to solve common problems involving these data structures.

Basic Data Structures

# Statement

Given a string containing an arithmetic expression, implement a basic calculator that evaluates the expression string. The expression string can contain integer numeric values and should be able to handle the "+" and "-" operators, as well as "()" parentheses. 

**Constraints:**

Let `s` be the expression string. We can assume the following constraints:

- $1 \leq$ `s.length` $\leq 3 \times 10^{3}$
- `s` consists of digits, "+", "-", "(", and ")".
- `s` represents a valid expression.
- "+" is not used as a unary operation ( $+1$ and $+(2 + 3)$ are invalid).
- "-" could be used as a unary operation ($-1$ and $-(2 + 3)$ are valid).
- There will be no two consecutive operators in the input.
- Every number and running calculation will fit in a signed 32-bit integer.


# Examples





Try to solve the Basic Calculator problem.