Longest Substring Without Repeating Characters

Given a string s, your task is to find the length of the longest substring without repeating characters. In other words, you need to compute the maximum possible value of \(\text{length} = i - j + 1\) over all indices such that the substring \(s[j \ldots i]\) contains all distinct characters.

The problem requires careful tracking of the most recent occurrence index for each character. A common approach is to use a sliding window along with a hash map (or direct indexing for ASCII) to efficiently update the start of the current window when a repeated character is encountered.

Example:

• For input "abcabcbb", the longest substring without duplicate characters is "abc" with a length of 3.
• For input "bbbbb", the longest substring is "b" with a length of 1.
• For input "pwwkew", the answer is 3 as the longest substring without repeating characters is "wke".

inputFormat

The input consists of a single line containing a string s composed of ASCII characters.

Input is provided via stdin.

outputFormat

Output a single integer representing the length of the longest substring of s that contains no repeated characters.

Output the result via stdout.

abcabcbb

3