System-Design-Question

Merge K Sorted Lists

Category: dsa Date: 2026-02-13

Merge K Sorted Lists System Design Discussion

1. Requirements (Functional + Non-functional)

2. High-Level Architecture

The high-level architecture of the system consists of the following components:

3. Database Design

Assuming an RDBMS (Relational Database Management System) like MySQL or PostgreSQL:

4. Scaling Strategy

To scale the system, we can:

5. Bottlenecks

Potential bottlenecks:

6. Trade-offs

Trade-offs:

Solution using the First Principle of System Design: Separation of Concerns

The first principle of system design is Separation of Concerns. In the context of the Merge K Sorted Lists problem, we can separate the concerns of:

By separating these concerns, we can design a modular system that is easier to maintain, scale, and extend.

Pseudocode

class ListMergingNode:
    def merge(self, list1, list2):
        # Merge two sorted lists
        result = []
        while list1 and list2:
            if list1.val <= list2.val:
                result.append(list1.val)
                list1 = list1.next
            else:
                result.append(list2.val)
                list2 = list2.next
        result.extend(list1 or list2)
        return result

class KListMerger:
    def merge_k_lists(self, lists):
        # Merge K sorted lists
        result = []
        priority_queue = []
        for list in lists:
            # Push each list onto the priority queue
            heapq.heappush(priority_queue, (list[0], list))
        while priority_queue:
            # Pop the smallest element from the priority queue
            val, list = heapq.heappop(priority_queue)
            result.append(val)
            # Push the next element from the list onto the priority queue
            if list.next:
                heapq.heappush(priority_queue, (list.next.val, list.next))
        return result

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