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Algorithms & data structures medium

Merge k sorted lists in Python using a heap

Merge k individually sorted lists into one sorted list in Python using a min-heap.

heapq merge sorted-list
Python 
import heapq

def merge_k_sorted_lists(lists):
    heap = []
    # Push the first element of each list onto the heap
    for i, lst in enumerate(lists):
        if lst:
            heapq.heappush(heap, (lst[0], i, 0))
    
    result = []
    while heap:
        val, list_idx, elem_idx = heapq.heappop(heap)
        re…
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