## Challenge Statement

- Given a string
*s*, find the length of the**longest substring**without repeating characters. - This challenge corresponds to LeetCode #3.

### Constraints

`0 <= s.length <= 5 * 10`

^{4}*s*consists of English letters, digits, symbols, and spaces.

**Example 1:**

**Input:** `s = "abcabcbb"`

**Output:** 3

**Explanation:** The answer is “abc”, with a 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 a length of 3.

Notice that the answer must be a substring, “pwke” is a subsequence and not a substring.

## Solution

Below is my solution and some test cases. The solution has a** linear time complexity of O(n)** and **constant space complexity O(1)**, where *n* is the number of characters in the input string.