Sliding Window Examples: Solved Problems with Step-by-Step Explanations
Learn the Sliding Window pattern through carefully selected examples. Each example includes problem statement, intuition, code in multiple languages, complexity analysis, and follow-up variations. Maintain a dynamic window to find optimal subarrays or substrings.
Example 1: Classic Problem (Easy)
Problem: Maximum Average Subarray
Description: Find contiguous subarray of length k with maximum average.
Approach: Fixed-size sliding window. Slide by adding new element and removing oldest.
Complexity: Time O(n), Space O(k)
Key Insight: This is a classic easy Sliding Window problem. Understanding this example helps you solve 5 similar problems.
Interview Tip: Explain your approach before coding. State the time and space complexity upfront.
Example 2: Interview Favorite (Medium)
Problem: Longest Substring Without Repeating Characters
Description: Find the length of the longest substring without duplicate characters.
Approach: Variable-size window with hash set. Expand right, shrink left when duplicate found.
Complexity: Time O(n), Space O(k)
Key Insight: This is a classic medium Sliding Window problem. Understanding this example helps you solve 5 similar problems.
Interview Tip: Explain your approach before coding. State the time and space complexity upfront.
Example 3: Advanced Application (Hard)
Problem: Minimum Window Substring
Description: Find the smallest window containing all characters of a target string.
Approach: Expand window to include all required chars, then shrink to find minimum.
Complexity: Time O(n), Space O(k)
Key Insight: This is a classic hard Sliding Window problem. Understanding this example helps you solve 5 similar problems.
Interview Tip: Explain your approach before coding. State the time and space complexity upfront.
Why These Examples Work
Each example was chosen because it:
Study the pattern, not just the solution. The goal is to recognize when to apply Sliding Window in new, unseen problems.
Pattern Recognition Checklist
Before coding, ask yourself:
If 2+ answers are yes, try the Sliding Window approach.
Categorization & Filters
Frequently Asked Questions
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