Longest Substring Without Repeating Characters

Given a string S, find the length of the longest substring that does not contain any repeating characters.

You are required to implement a solution using a sliding window technique. More formally, if you maintain two pointers l (left) and r (right), the length of the current substring is given by \( r - l + 1 \). Your task is to compute the maximum value of this quantity over all substrings of S that do not contain duplicate characters.

Example:

• For S = "abcabcbb", the answer is 3 because the longest substring without repeating characters is "abc".
• For S = "bbbbb", the answer is 1 because the longest substring without repeating characters is "b".
• For S = "pwwkew", the answer is 3 because the longest substring without repeating characters is "wke".

inputFormat

The input consists of a single line containing the string S (which may be empty) composed of ASCII characters.

outputFormat

Output a single integer which is the length of the longest substring of S that does not contain repeating characters.

abcabcbb

3