K Way Merge

The K-Way Merge coding pattern is a technique used to merge multiple sorted arrays, lists, or other data structures into a single sorted result. It’s an extension of the Merge operation used in merge sort. The “K” in K-Way represents the number of sorted arrays being merged.

Here’s a brief explanation of how the K-Way Merge pattern works:

1. Initialize Min-Heap: Create a min-heap (priority queue) and add the first element from each of the K sorted arrays. The min-heap ensures that the smallest element is always at the top.
2. Pop and Add: While the min-heap is not empty:
   • Pop the smallest element from the min-heap. This element will be the next element in the merged result.
   • If there are more elements in the same source array from which the popped element came, add the next element from that array to the min-heap.
3. Repeat: Continue popping and adding elements from the min-heap until all elements are processed.

The K-Way Merge pattern is particularly useful when you have limited memory available, as it doesn’t require loading all elements into memory at once. Instead, it works with a small number of elements from each array, keeping memory usage under control.

This pattern is often used in scenarios such as external sorting, where data doesn’t fit entirely in memory, or in distributed systems where data is stored across multiple machines.

Implementing the K-Way Merge pattern involves using data structures like min-heaps (priority queues) and careful iteration over the arrays to ensure efficient merging.

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