MediumHigh Frequency25 min
Merge Lists & K-way Merge
Merge sorted lists using dummy node technique and a min-heap for K lists.
Merge two sorted linked lists by always picking the smaller head. Use a dummy node to avoid edge cases.
Merge Two Sorted Linked Lists
Merge Visualization
Linked List1 / 5
List1: 1→3. List2: 2→4
Two sorted lists. Use dummy head. tail = dummy.
Code
Merge Two Lists
O(m+n)O(1) space — no extra array, just pointer rewiringStep-by-step1 / 4
Dummy→null. l1=1, l2=2
Initialize dummy and tail.
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