Longest Non-Repeating Substring Length

Problem Statement

Given a string, determine the length of the longest substring that contains no repeating characters.

Examples

Example 1:

Input: "abcaabcd"
Output: 4
Explanation: The longest substring without repeating characters is 
"abca" or "abcd", both with length 4.
        

Example 2:

Input: "lllll"
Output: 1
Explanation: The longest non-repeating substring is "l" with length 1.
        

Example 3:

Input: "xyzzyx"
Output: 3
Explanation: The longest substring without repeating characters is
 "xyz" with length 3.
Note that "xyzz" is not valid as it contains repeating 'z's.
        

Constraints

• 1 ≤ length of the string ≤ 5 × 10⁴
• The string consists of English letters, digits, symbols, and spaces.