Sliding Window vs Two Pointers
Learn when to use each pattern and make the right choice in your coding interview.
Quick Answer
Use Sliding Window when you need to find a contiguous subarray/substring that meets a condition
Use Two Pointers when you need to find pairs or compare elements from both ends
Side-by-Side Comparison
Sliding Window
Best For
Subarray sum, longest substring, window constraints
Time
O(n)
Space
O(1) or O(k)
Two Pointers
Best For
Pair finding, palindrome checking, sorted array problems
Time
O(n)
Space
O(1)
How to Decide
- Is the problem about a contiguous subarray/substring? → Sliding Window
- Are you comparing elements from opposite ends? → Two Pointers
- Need to find pairs that sum to target? → Two Pointers
- Looking for longest/shortest window with constraint? → Sliding Window
Practice Both Patterns
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