Longest Contiguous Stretch of Distinct Characters in a String

Given a string `s`, return the length of the longest substring of `s` in which every character differs from every other character. A substring is a contiguous block of characters of `s`. The empty string counts as a substring, so an empty input has answer 0. Characters are compared exactly as given: an uppercase letter and its lowercase form are different characters, and spaces, digits and punctuation are ordinary characters that can repeat like any other. ### Function Signature ```python def longest_distinct_substring_length(s: str) -> int: ``` ### Rules - Only contiguous substrings count. Picking characters that are not adjacent in `s` does not form a substring. - Return only the length. Several different substrings may share the maximum length; the length is still a single, unique answer. ### Constraints - `0 <= len(s) <= 50000` - Every character of `s` is printable ASCII (character codes 32 through 126): letters, digits, symbols and the space character. - Because there are only 95 such characters, the answer is between 0 and `min(len(s), 95)`. ### Examples **Example 1** ```text Input: s = "streets" Output: 4 ``` The substring "stre" has four distinct characters. Making it one character longer would include a second "e", and no substring of five or more characters is free of repeats. **Example 2** ```text Input: s = "aAbBa" Output: 4 ``` "aAbB" and "AbBa" both have four distinct characters, because "a" and "A" are different. The whole string repeats "a". **Example 3** ```text Input: s = "" Output: 0 ``` The only substring of the empty string is the empty string itself.