These are Data Structures questions of the kind Meta actually asks — the patterns reported from Meta's AI-engineering rounds, where design trade-offs, scale and failure modes matter as much as definitions. Treat this page as a mock interview: say every answer out loud before revealing it. If one surprises you, the lesson behind it is linked at the bottom.
Meta Data Structures concept questions
Clone an undirected graph: given one node, return a deep copy of the whole connected graph. What structure prevents infinite loops, and why is it also the answer map?
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Meta Data Structures applied & hands-on questions
Count the subarrays of [3, 4, -7, 1, 3, 3, 1, -4] summing to exactly 7. O(n) — the trick is a hash map of prefix sums.
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Return the values visible when the tree is viewed from the right — the last node of every level. Which traversal fits, and why?
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How to use this page: Meta rarely asks something you've never seen — they ask a standard Data Structures concept and then push one level deeper ("why?", "what would you do if..."). Master the concept in the Data Structures course lessons, and the follow-up stops being scary.
Keep practising: Hash Tables, Linked Lists, Heaps and Choosing the Right Structure cover what most Meta Data Structures rounds test.