Longest Substring Without Repeating Characters

Hard
Description:

Given a string s, find the length of the longest substring without duplicate characters.

Example 1:
Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.

Input Format:

A single string s consisting of lowercase and/or uppercase English letters.

Output Format:

An integer representing the length of the longest substring without repeating characters.

Tags:
Hashing Sliding Window Two Pointers
Sample Input:
abcabcbb
Sample Output:
3