006-Longest-Substring-With-Without-Repetition.md

Description

Imagine you are working on a text processing feature for a text editor that needs to find the longest substring within a given text. You need to implement two functions:

1. One to find the longest substring without repeating characters.
2. One to find the longest substring with at most two repeating characters.

Requirements

1. Function Signature:

   public int LongestSubstringWithoutRepetition(string s);
   public int LongestSubstringWithTwoRepeatingCharacters(string s);

2. Input:

   • s: A string representing the text to be processed.

3. Output:

   • Return an integer representing the length of the longest substring that meets the criteria.

4. Constraints:

   • The input string s consists of English letters, digits, symbols, and spaces.

Extra Credit:

• Modify the function to handle Unicode characters efficiently.

Example:

string s = "abcabcbb";
int resultWithoutRepetition = LongestSubstringWithoutRepetition(s); // Expected output: 3
int resultWithTwoRepeating = LongestSubstringWithTwoRepeatingCharacters(s); // Expected output: 7

The function should return:

int resultWithoutRepetition = LongestSubstringWithoutRepetition(s);
// Expected output: 3
int resultWithTwoRepeating = LongestSubstringWithTwoRepeatingCharacters(s);
// Expected output: 7

Hints:

• Use a sliding window approach to maintain the current substring.
• Use a hash set or hash map to track characters in the current window.

Sample Dataset:

string s = "pwwkew";

Expected Output for Sample Dataset:

int resultWithoutRepetition = LongestSubstringWithoutRepetition(s);
// Expected output: 3
int resultWithTwoRepeating = LongestSubstringWithTwoRepeatingCharacters(s);
// Expected output: 4