Longest Substring Without Repeating Characters

longest_substring_without_ repeating_characters.text

Question:
  Given a string s, find the length of the longest substring without repeating characters.
 
Solution:
  using sliding window technique and hash map.
  
  Window Sliding Technique is a computational technique that aims to reduce the use of nested loops and replace it with a single loop, thereby reducing the time complexity.
  
  steps:
    1. Initialize two pointers, 'start' and 'end,' both pointing to the start of the string.
    2. Initialize an empty hash set to store the unique characters.
    3. Initialize a variable 'maxLen' to store the maximum length encountered so far.
    4. Iterate through the string with the 'end' pointer:
      a. Check if the current character at 'end' is already in the hash set.
        . If it is, remove the character at 'start' from the hash set and increment 'start' by 1.
        . If it is not, add the current character to the hash set, calculate the length of the current substring (end - start + 1), and update 'maxLen' if necessary.
    5. Repeat step 4 until the 'end' pointer reaches the end of the string.
    6. Return 'maxLen' as the result.
    
   
   
Time complexity: O(N), Where N is the length of the input string. 
Space complexity: O(1).


https://leetcode.com/problems/longest-substring-without-repeating-characters/