Solve the Easy-level Reverse a String coding interview problem online in Python & JavaScript. Run your code against real test cases in the browser and study worked examples. It covers strings. Read the step-by-step solution and complexity analysis. Java starter code is also included for reference (no in-browser JVM yet, so it can't be run here).

Reverse a String – Solve Online in Python & JavaScript

## Problem Description

Given a string `s`, write a function `reverse_string(s: str) -> str` to reverse the input string and return the reversed string as output.

## Function Signature

```python
def reverse_string(s: str) -> str:
```

## Output

The reversed string of `s`.

## Example

```python
assert reverse_string("hello") == "olleh"
assert reverse_string("Tesla") == "alseT"
assert reverse_string("12345") == "54321"
```

- The task is to reverse a given string `s`.
- We cannot use built-in reverse functions or slicing, so we’ll use a two-pointer approach to reverse the string by swapping characters from each end.

Understanding the Problem

- Set up two pointers: `left` starting at the beginning of the string (0) and `right` starting at the end (length - 1).
- These pointers will move towards each other, swapping characters until they meet in the middle.

Initialize Two Pointers

- Inside a loop, swap the characters at `left` and `right` by storing one in a temporary variable.
- After each swap, increment `left` and decrement `right` to move towards the center of the string.

Swap Characters Using a Third Variable

- Handle edge cases, including:
  - Empty strings, which should return an empty string.
  - Single-character strings, which should return the string itself.
  - Strings with spaces or special characters, which should be reversed as normal.