📊 Sliding Window Problems
Welcome to the Sliding Window section of JDCodebase!
The Sliding Window technique is one of the most powerful tools to optimize brute-force solutions for problems involving arrays or strings. It helps reduce nested loops and improve time complexity from O(n²) to O(n) in many real-world DSA problems.
🔍 What is Sliding Window?
It’s a technique where you maintain a window (subarray or substring) that slides over the input data to process only the required portion at a time. You either:
- Fix the size of the window (e.g., size = k)
- Or vary the window dynamically based on conditions
🤔 When to Use Sliding Window?
- Subarrays/substrings with max/min sum, length, or frequency
- Count of distinct/repeating elements in a window
- Checking existence of patterns in a range (e.g., anagrams)
- Problems that ask for optimal results over consecutive elements
⚙️ How Sliding Window Works?
- Initialize two pointers –
leftandright - Expand the window by moving the
rightpointer - Shrink the window by moving the
leftpointer when constraints are violated - Update the result (max/min/count) during the process
🧠 Common Patterns
- Maximum sum of subarray of size k
- Longest substring with k distinct characters
- Smallest subarray with a sum ≥ target
- Find all anagrams of a pattern in a string
- Longest substring without repeating characters