Longest Substring Without Repeating Characters

Problem Statement

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

Examples

Example 1
Input: s = "abcabcbb"
Output: 3
Explanation: The longest substring without repeating characters is "abc", with a length of 3. Other valid substrings include "bca" and "cab".

Example 2
Input: s = "bbbbb"
Output: 1
Explanation: The longest substring without repeating characters is "b", with a length of 1.

Example 3
Input: s = "pwwkew"
Output: 3
Explanation: The longest substring without repeating characters is "wke", with a length of 3. Note that "pwke" is a subsequence, not a substring.

Constraints

0 <= s.length <= 5 * 10^4
s consists of English letters, digits, symbols, and spaces.

Code Template

class Solution:
    def lengthOfLongestSubstring(self, s: str) -> int:
        # Write your code here
        pass

Solutions

Solution 1: This approach uses a sliding window technique with a set to track characters in the current substring. The time complexity is O(n) and space complexity is O(min(m, n)), where m is the size of the character set and n is the length of the string.

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Notes