String + Array Interview Questions list

 String-Based Questions

1. Reverse a string — without using built-ins.
2. Is it a palindrome? Let's find out.
3. Remove duplicates from a string — efficiently.
4. First non-repeating character — who stands alone?
5. Count how many times each character appears.
6. Flip the words in a sentence, not the letters.
7. Are two strings anagrams? Prove it.
8. Longest substring without repeats — sliding window style.
9. Build your own atoi — string to integer.
10. Compress strings with run-length encoding.
11. Most frequent character — who dominates?
12. List all possible substrings of a string.
13. Is one string a rotation of another?
14. Strip all white spaces from a string.
15. Is this a valid shuffle of two strings?
16. Convert text to Title Case — properly.
17. Find the longest common prefix among words.
18. Break a string into a char array — without confusion.
19. Replace spaces with %20 — classic URL trick.
20. Turn full sentences into acronyms.
21. Check if the string is all digits — no alphabets allowed.
22. Count how many words are in the string.
23. Remove a specific character — cleanly.
24. Find the shortest word in a sentence.
25. Longest palindromic substring — two-pointer style.

Array-Based Questions

26. Reverse an array in-place.
27. Find the largest and smallest element.
28. Check for duplicates in an array.
29. Remove duplicates — return only unique values.
30. Find the missing number from 1 to N.
31. Move all zeros to the end — keep order.
32. Rotate the array left/right by K positions.
33. Find the Kth largest/smallest element.
34. Merge two sorted arrays — without using extra space.
35. Find the intersection of two arrays.
36. Sort 0s, 1s, and 2s without using sort().
37. Find subarrays with a given sum.
38. Detect if a subarray sums to 0.
39. Find the longest increasing subsequence.
40. Kadane’s Algorithm — maximum subarray sum.
41. Check if the array is sorted and rotated.
42. Rearrange the array in max-min order alternately.
43. Find leaders in an array (no greater element to the right).
44. Calculate the frequency of all elements in O(n).
45. Product of all elements except self.

Drupal 10 vs. Previous Versions: Key Performance Enhancements

 Drupal 10 introduced several key improvements that enhance performance, developer experience, and maintainability compared to Drupal 9 and earlier versions. Here are some of the major performance-related improvements:

1. Symfony 6 & PHP 8.1/8.2 Support

Drupal 10 runs on Symfony 6, a faster and more efficient framework than Symfony 4 

 (used in Drupal 9).

Full support for PHP 8.1 and 8.2 enables:

    JIT (Just-in-Time) compilation.

    Better memory usage and execution speed.

    Performance boosts from language-level improvements.

2. Modern JavaScript Components (Replacing jQuery UI)

Many legacy jQuery components have been removed or replaced with modern JavaScript, reducing page weight and improving frontend performance.

 Example: Dialogs and UI widgets are now implemented using more efficient libraries or custom JavaScript.

3. CKEditor 5 (Replacing CKEditor 4)

CKEditor 5 is significantly faster, more modular, and more lightweight.

Better for authoring performance and loading times in admin UI.

4. Theme Optimization (Olivero & Claro)

The new Olivero (frontend) and Claro (admin) themes are built with performance in mind:

    Modern CSS grid layout.

    Fewer dependencies.

    Accessible and responsive by default, reducing custom tweaks that slow rendering.

5. Cleaner Codebase (Deprecated Code Removed)

All deprecated APIs from Drupal 8 and 9 have been removed.

Leaner core = fewer slowdowns from legacy code paths.

Helps PHP Opcache and autoloaders work more efficiently.

 6. More Efficient Module Handling

Optional modules like Aggregator, HAL, RDF, and Color have been removed or deprecated.

Reduces overhead from unused code and services being bootstrapped.

7. Improved Cache System

Core improvements to caching (dynamic page cache, render cache) have continued in Drupal 10.

Caching is more consistent and reliable due to underlying framework upgrades.

8. Better Support for Lazy Loading

Media and images in Drupal 10 benefit from native support for loading="lazy".

Helps reduce initial page load time, especially on media-heavy sites.

9. Configurable Performance Modules

Tools like BigPipe (for streaming content), and the core Performance module (for JS/CSS aggregation and caching) are better integrated.