1. Find the maximum sum of a subarray of size k in a given array.
2. Count the number of substrings with exactly k distinct characters.
3. Find the length of the longest substring without repeating characters.
4. Given an array, find the minimum sum of a subarray of size k.
5. Count occurrences of anagrams of a string in another string.
6. Find the first negative integer in every window of size k.
7. Find the average of all contiguous subarrays of size k.
8. Given a string, find the longest substring with at most two distinct characters.
9. Check if the given string contains all characters of another string using a sliding window.
10. Find the maximum product of a subarray of size k.
11. Given an array of integers, find the number of subarrays with a sum equal to a given value.
12. Find the length of the longest substring with at most k distinct characters.
13. Find the longest palindromic substring using the sliding window technique.
14. Given two strings, find the minimum window substring of the first string that contains all characters of the second string.
15. Find all unique characters in a string using a sliding window.
16. Check if a string can be rearranged to form a palindrome using a sliding window.
17. Count all substrings of a string that contain at most k characters.
18. Find the maximum length of a subarray with a sum less than or equal to k.
19. Given an array, find the maximum sum of any continuous subarray.
20. Find the longest substring with at least k repeating characters.
21. Given a string, check if it can be segmented into words from a given dictionary.
22. Find the longest sequence of contiguous integers in an array using a sliding window.
23. Find the smallest window in a string that contains all characters of another string.
24. Given an array, find the number of distinct elements in every window of size k.
25. Find the maximum sum of any k-length contiguous subarray.
26. Check if a given string is a permutation of another string.
27. Find the longest substring with exactly k characters.
28. Given an array of integers, return the first repeating element in the array.
29. Find the smallest subarray with a sum greater than a given value.
30. Given an array, return the sum of all elements in every window of size k.
31. Find the longest substring of a string that contains only one character.
32. Given a string, find the first non-repeating character using a sliding window.
33. Find the maximum number of vowels in any substring of length k.
34. Given a string, find the maximum length of a substring with balanced parentheses.
35. Find the longest substring of distinct characters in a string.
36. Given an array, return the maximum number of consecutive ones in it.
37. Find the minimum length of a subarray that has a sum greater than or equal to a target value.
38. Given a string, find the number of substrings with a length greater than k.
39. Find the minimum number of characters to be added to make a string a palindrome.
40. Given an array, find the smallest subarray with a maximum sum.