Core Data Structures Warmup
Two quick whiteboard questions on array vs linked list complexity and hash-map two-sum. Five minutes each.
Question Bundle
JavaScript
2 questions
fundamentals
arrays
hash-map
warmup
By @ezb1981
April 11, 2026
·
Updated May 20, 2026
1,063 views
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3.5 (25)
What is the time complexity of inserting at the beginning of an array vs a linked list?
Given an integer array, write a function that returns true iff there exist two values that sum to a target. Walk through your approach and the complexity.