Explain the Merge K-Sorted Lists algorithm and its complexity.
This question covers merging multiple sorted linked lists. It tests heap/priority queue knowledge.
Why Interviewers Ask This
Merging sorted streams is a common pattern in big data. Interviewers ask this to test your ability to optimize merge operations. It demonstrates mastery of advanced data structures.
How to Answer This Question
Describe using a min-heap to pick the smallest head among k lists. Pop min, add to result, push next node from same list. Complexity is O(N log K).
Key Points to Cover
- Min-heap usage
- Time complexity
- Iterative extraction
- Space optimization
Sample Answer
We use a min-heap to efficiently merge K sorted lists. Initially, push the head of each list into the heap. Repeatedly extract the minimum element, append it to the result, and insert the next node from that list into th…
Common Mistakes to Avoid
- Using linear scan for min
- Ignoring empty lists
- Incorrect heap size
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