Reverse the Characters of an ASCII String
Company: Amazon
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
Write a function that returns a string with its characters in reverse order.
The report names this warm-up only as reversing a string. This version fixes the input to printable ASCII, so that reversing characters and reversing bytes give the same result, and asks for the reversed string as the return value.
### Function Signature
```python
def reverse_string(s: str) -> str:
```
### Rules
- Return a string of the same length whose character at index `i` is `s[len(s) - 1 - i]`.
- Every character moves, including spaces and punctuation; nothing is trimmed, collapsed or changed in case.
- An empty input returns an empty string.
### Constraints
- `0 <= len(s) <= 10^5`
- `s` contains only printable ASCII characters (codes 32 to 126).
### Examples
**Example 1**
```text
Input: s = "firmware"
Output: "erawmrif"
```
**Example 2**
```text
Input: s = "a b!"
Output: "!b a"
```
The space and the exclamation mark move like any other character.
**Example 3**
```text
Input: s = ""
Output: ""
```
Overview: A warm-up coding task that asks for the characters of a printable ASCII string in reverse order, with spaces and punctuation moved like any other character. It checks basic index handling and edge cases such as the empty string and very long inputs.
Write a function `reverse_string(s)` that returns the string `s` with its characters in reverse order.
The input is restricted to printable ASCII, so reversing characters and reversing bytes give the same result. Return the reversed string as the function's return value.
### Rules
- Return a string of the same length whose character at index `i` is `s[len(s) - 1 - i]`.
- Every character moves, including spaces and punctuation; nothing is trimmed, collapsed or changed in case.
- An empty input returns an empty string.
### Constraints
- `0 <= len(s) <= 10^5`
- `s` contains only printable ASCII characters (codes 32 to 126).
- No value in this problem exceeds 2^31 - 1.
### Examples
**Example 1**
```text
Input: s = "firmware"
Output: "erawmrif"
```
**Example 2**
```text
Input: s = "a b!"
Output: "!b a"
```
The space and the exclamation mark move like any other character.
Constraints
- 0 <= len(s) <= 10^5
- s contains only printable ASCII characters (codes 32 to 126)
Examples
Input: ('',)
Expected Output: ''
Explanation: Minimum valid: an empty string returns an empty string.
Input: ('Q',)
Expected Output: 'Q'
Explanation: Minimum valid: a single character returns itself.
Hints
- For each output position i, work out which input position supplies its character.
- Spaces, punctuation, quotes and backslashes are ordinary characters here: nothing is trimmed, collapsed or re-cased.
- Check your approach on lengths 0, 1, 2 and 3 before trusting it on longer strings.