public class Solution
extends Object
3 - Longest Substring Without Repeating Characters\.
Medium
Given a string `s`, find the length of the **longest substring** without repeating characters.
**Example 1:**
**Input:** s = "abcabcbb"
**Output:** 3
**Explanation:** The answer is "abc", with the length of 3.
**Example 2:**
**Input:** s = "bbbbb"
**Output:** 1
**Explanation:** The answer is "b", with the length of 1.
**Example 3:**
**Input:** s = "pwwkew"
**Output:** 3
**Explanation:** The answer is "wke", with the length of 3. Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
**Example 4:**
**Input:** s = ""
**Output:** 0
**Constraints:**
* 0 <= s.length <= 5 * 104
* `s` consists of English letters, digits, symbols and spaces.