Your question is Longest Unique Message Substring. Start with the requirements on the right.
Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.
In Providence messaging and note-entry surfaces, repeated characters can appear in free-text input. Write a function that returns the length of the longest substring in a string s that contains no repeated characters.
ss with all unique charactersA substring must be contiguous. The function should run efficiently for large inputs.
def length_of_longest_substring(s):