def longest_unique_substring(s: str) -> str: """ Given a string , return the longest unique substring that occurs within . A unique substring is a substring within which DOES NOT have any repeating characters. As an example, "xd" is unique but "xxd" is not. If there are two equal length unique substrings within , return the one that starts first (i.e., begins at a smaller index). tips: In order to get your function to run fast, consider using a dictionary to store the indexes of previously seen characters, from there, you can follow a set of rules based on each new character you see to determine the length of the longest unique substring seen so far. >>> longest_unique_substring('aab') 'ab' """ RESTRICTIONS: - Do not add any imports and do it on python .Do not use recursion. Do not use break/continue.Do not use try-except statements.
def longest_unique_substring(s: str) -> str:
"""
Given a string <s>, return the longest unique substring that occurs within
<s>.
A unique substring is a substring within <s> which DOES NOT have any
repeating characters. As an example, "xd" is unique but "xxd" is not.
If there are two equal length unique substrings within <s>, return the one
that starts first (i.e., begins at a smaller index).
tips:
In order to get your function to run fast, consider using a dictionary to
store the indexes of previously seen characters, from there, you can
follow a set of rules based on each new character you see to determine
the length of the longest unique substring seen so far.
>>> longest_unique_substring('aab')
'ab'
"""
RESTRICTIONS:
- Do not add any imports and do it on python .Do not use recursion. Do not use break/continue.Do not use try-except statements.
![](/static/compass_v2/shared-icons/check-mark.png)
Step by step
Solved in 2 steps with 1 images
![Blurred answer](/static/compass_v2/solution-images/blurred-answer.jpg)
![Database System Concepts](https://www.bartleby.com/isbn_cover_images/9780078022159/9780078022159_smallCoverImage.jpg)
![Starting Out with Python (4th Edition)](https://www.bartleby.com/isbn_cover_images/9780134444321/9780134444321_smallCoverImage.gif)
![Digital Fundamentals (11th Edition)](https://www.bartleby.com/isbn_cover_images/9780132737968/9780132737968_smallCoverImage.gif)
![Database System Concepts](https://www.bartleby.com/isbn_cover_images/9780078022159/9780078022159_smallCoverImage.jpg)
![Starting Out with Python (4th Edition)](https://www.bartleby.com/isbn_cover_images/9780134444321/9780134444321_smallCoverImage.gif)
![Digital Fundamentals (11th Edition)](https://www.bartleby.com/isbn_cover_images/9780132737968/9780132737968_smallCoverImage.gif)
![C How to Program (8th Edition)](https://www.bartleby.com/isbn_cover_images/9780133976892/9780133976892_smallCoverImage.gif)
![Database Systems: Design, Implementation, & Manag…](https://www.bartleby.com/isbn_cover_images/9781337627900/9781337627900_smallCoverImage.gif)
![Programmable Logic Controllers](https://www.bartleby.com/isbn_cover_images/9780073373843/9780073373843_smallCoverImage.gif)