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 * 104
  • 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.