AlgoSolveoRoadmap › Stage 2: Arrays & Strings › Pattern 7 of 53
DSA pattern guide
Array — Sliding Window
Contiguous subarray, "longest/shortest/max sum" with a size k or a condition.
Use it when
Contiguous subarray, "longest/shortest/max sum" with a size k or a condition.
Key idea
Grow the right edge, shrink the left edge when the window breaks the rule. Keep a running sum or count instead of recomputing.
Practice problems, in order
- Maximum Sum Subarray of Size KEasy
- Max Consecutive OnesEasy
- Max Consecutive Ones IIIMedium
- Subarray Product Less Than KMedium
- Fruits Into BasketsMedium
- Minimum Size Subarray SumMedium
- Sliding Window MaximumHard
- Subarray with K Distinct IntegersHard
How to practise this pattern
- Read the problem and look for the signal above before writing any code.
- Say the brute force out loud, with its time complexity, then ask what work it repeats.
- Apply the key idea and write the optimised version yourself.
- If you're stuck for more than 10 minutes, take one small hint, not the full solution.
- Move to the next problem only when you can explain why this pattern fits.
Stuck on one of these?
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