Data structures and algorithms essentials check

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Question 1 of 14What is the typical time complexity of scanning every item in an array once?

O(n)O(1)O(n²)

Question 2 of 14What is the typical time complexity of accessing an array element by a known index?

O(1)O(n)O(log n)

Question 3 of 14Which structure is especially useful for detecting whether a value has already been seen?

SetQueueLinked list

Question 4 of 14Which problem is a natural fit for a two-pointer approach?

Comparing characters from both ends of a string to test whether it is a palindromeJoining two relational database tablesSending an HTTP request to a server

Question 5 of 14Which type of problem is especially suited to the sliding-window pattern?

Problems involving a contiguous subarray or substringFinding only a tree node's parent referenceDefining a relational database schema

Question 6 of 14Which ordering rule does a stack follow?

Last in, first outFirst in, first outSmallest value always leaves first

Question 7 of 14Which data structure is commonly used for breadth-first search?

QueueStackSet without any traversal order

Question 8 of 14What is the typical complexity of locating the item at position n in a singly linked list when only the head is known?

O(n)O(1)O(log n)

Question 9 of 14What prevents a recursive function from calling itself forever?

A reachable base caseA hash functionA queue capacity limit

Question 10 of 14Which traversal family includes preorder, inorder, and postorder traversal?

Depth-first traversalBreadth-first traversalHash traversal

Question 11 of 14Why is a visited set commonly used when traversing a graph?

To avoid repeatedly processing nodes reached through cycles or multiple pathsTo automatically sort all graph edgesTo permanently delete traversed vertices

Question 12 of 14What is the typical time complexity of binary search on sorted indexed data?

O(log n)O(n)O(n²)

Question 13 of 14What does ordinary binary search require about the input?

The search space must be orderedEvery value must occur more than onceThe data must be stored in a linked list

Question 14 of 14Which complexity is commonly targeted by efficient general-purpose comparison sorting algorithms?

O(n log n)O(1)O(2ⁿ)

Choose one answer for every question, then check your answers.