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Longest Substring Without Repeating Characters

Certification: Intermediate Level Accuracy: 0% Submissions: 0 Points: 10

Write a JavaScript program to find the length of the longest substring without repeating characters in a given string. A substring is a contiguous sequence of characters within a string.

Example 1
    
  
  • Input: s = "abcabcbb"
    • 
  
  • Output: 3
    • 
  
  • Explanation: 
    • The string "abcabcbb" contains multiple substrings without repeating characters.
    • The longest substring without repeating characters is "abc" with length 3.
    • Other substrings like "bca" and "cab" also have length 3, but no substring is longer.
    • Therefore, the answer is 3.
    •
Example 2
    
  
  • Input: s = "bbbbb"
    • 
  
  • Output: 1
    • 
  
  • Explanation: 
    • The string "bbbbb" consists of only one character repeated.
    • The longest substring without repeating characters is "b" with length 1.
    • Any substring longer than 1 would contain repeating characters.
    • Therefore, the answer is 1.
    •
Constraints
    
  
  • 0 ≤ s.length ≤ 5 * 10^4
    • 
  
  • s consists of English letters, digits, symbols and spaces
    • 
  
  • Time Complexity: O(n)
    • 
  
  • Space Complexity: O(min(m,n)) where m is the size of the charset
    •
StringsAlgorithmsKPMGPhillips
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Hint
Solution

Solution Hints

    
  
  • Use the sliding window technique with two pointers (left and right)
    • 
  
  • Maintain a set or map to track characters in the current window
    • 
  
  • Expand the right pointer and add characters to the tracking structure
    • 
  
  • When a duplicate is found, shrink the window from the left until no duplicates exist
    • 
  
  • Keep track of the maximum window size encountered during the process
    •

Steps to solve by this approach:

 Step 1: Initialize variables for maximum length, left pointer, and a set to track characters.
 Step 2: Use right pointer to expand the window by iterating through the string.
 Step 3: If current character is already in the set, shrink window from left until duplicate is removed.
 Step 4: Add current character to the set and update maximum length if current window is larger.
 Step 5: Continue until right pointer reaches the end of the string.
 Step 6: Return the maximum length found during the process.

Submitted Code :