Merge Sort
1 problems · 0 with full explanations
0 Easy0 Medium0 Hard
Merge sort divides an array into two halves, sorts each, and merges. It runs in O(n log n) worst case with O(n) extra space. The merge step can count inversions or merge sorted linked lists. Stable sort — relative order of equal elements is preserved.
How to practice
To practice Merge Sort problems effectively, start with the Easy problems listed below, trace through each solution on paper, then re-implement without looking. When you can recognise the merge sort pattern within 30 seconds of reading a new problem, move on to Medium difficulty. Use the related topic pages and our study guide for a structured progression.