How to solve Longest Substring Without Repeats
One approach is: Use a sliding window with last-seen character indexes. The reference code demonstrates this method. Compare the example and edge-case tests, then consider time and space usage.
Time and space complexity
Discuss the dominant operations and any additional data structures used by your implementation.
Practise and improve
Choose JavaScript, TypeScript or Python, complete the starter code, then select Run Tests. Request a hint when you need guidance, or choose View solution and confirm if you would like to study the reference implementation.