Sliding Window coding problems

Sliding window problems ask for the best subarray or substring under a rule: longest without repeats, fixed-size maximum sum, at most k distinct. Learn when the window grows, when it shrinks and what you keep inside it.

39 problems: 9 easy, 26 medium, 4 hard. Free to read; a free account solves them and earns XP and Aura.

1. Count Elements Less Than K in WindowPractice · +10 XP · sliding window, countingeasy
2. Count Even Numbers in WindowPractice · +10 XP · sliding window, arrayseasy
3. Count Max Element in WindowPractice · +10 XP · sliding window, arrayseasy
4. Count Non-Negative SubarraysPractice · +10 XP · sliding window, prefix sums, arrayseasy
5. Count Pairs with Specific SumPractice · +10 XP · sliding window, two pointers, arrayseasy
6. Count Subarrays with Target SumPractice · +10 XP · sliding window, prefix sums, hash mapeasy
7. Find Max Element in WindowPractice · +10 XP · sliding window, arrays, maximumeasy
8. Maximum Sum of a Fixed-Size SubarrayPractice · +10 XP · sliding window, arrays, prefix sumseasy
9. Sum of Elements in WindowPractice · +10 XP · sliding window, arrayseasy
10. Count Subarrays with Distinct ElementsPractice · +20 XP · hash map, sliding window, two pointersmedium
11. Distinct Elements in a Sliding WindowPractice · +20 XP · arrays, hash map, sliding windowmedium
12. Distinct Elements in Sliding WindowPractice · +20 XP · stack, hash map, sliding windowmedium
13. Find Minimums in Sliding WindowsPractice · +20 XP · heaps, sliding window, dequemedium
14. Largest Element in PrefixPractice · +20 XP · queue, monotonic deque, simulationmedium
15. Longest Alternating SubstringPractice · +20 XP · strings, sliding windowmedium
16. Longest Prefix With Maximum FrequencyPractice · +20 XP · queue, simulation, monotonic dequemedium
17. Longest Prefix With No RepeatsPractice · +20 XP · strings, sliding window, hash setmedium
18. Longest Segment with At Most K Distinct ElementsPractice · +20 XP · sliding window, hash map, frequency countingmedium
19. Longest Sorted SubsegmentPractice · +20 XP · two pointers, arrays, sliding windowmedium
20. Longest Subarray with Alternating ParityPractice · +20 XP · sliding window, two pointers, paritymedium
21. Longest Subarray with At Most K Distinct ElementsPractice · +20 XP · two pointers, sliding window, hash mapmedium
22. Longest Subarray with At Most K Duplicate PairsPractice · +20 XP · sliding window, hash map, arraysmedium
23. Longest Subarray with Bounded DifferencePractice · +20 XP · two pointers, sliding window, data structuresmedium
24. Longest Subarray with Equal HalvesPractice · +20 XP · sliding window, prefix sums, hash mapmedium
25. Longest Subarray with Increasing SumPractice · +20 XP · two pointers, subarray, sliding windowmedium
26. Longest Subarray with Limited DifferencePractice · +20 XP · two pointers, sliding window, greedymedium
27. Longest Subarray with Sum at Most KPractice · +20 XP · sliding window, prefix sums, two pointersmedium
28. Longest Subarray With Sum XPractice · +20 XP · sliding window, prefix sums, hash mapmedium
29. Longest Substring With At Most K Distinct CharactersPractice · +20 XP · strings, sliding window, hash mapmedium
30. Longest Substring Without RepeatsPractice · +20 XP · sliding window, hash map, stringsmedium
31. Maximum Subarray Sum with Fixed LengthPractice · +20 XP · queue, sliding window, prefix summedium
32. Optimal Training ScheduleOpen now · Weekly · +40 XP · +15 Aura · two pointers, sliding window, prefix sum1 solvedmedium
33. Sliding Window MinimumPractice · +20 XP · queue, sliding window, monotonic dequemedium
34. String with Most Unique CharactersPractice · +20 XP · strings, sliding window, hash mapmedium
35. Sum of Two Adjacent ElementsPractice · +20 XP · recursion, sliding window, prefix summedium
36. Longest Subarray with Distinct ElementsPractice · +30 XP · hash map, sliding window, two pointershard
37. Minimize Maximum Difference of Elements in IntervalsPractice · +30 XP · heaps, sliding window, greedyhard
38. Minimum Cost Subarray with Sum at Least KPractice · +30 XP · sliding window, prefix sums, monotonic queuehard
39. Minimum Window SubstringPractice · +30 XP · sliding window, two pointers, stringshard