Data Structures Data Structures 4

Question 1

You need to check whether a string of brackets like "{[()]}" is balanced. Which data structure fits best?

Accepted Answer

Stack

Answer

Push opening brackets and pop to match each closing bracket, which is exactly LIFO stack behavior.

Question 2

Which data structure does breadth-first search (BFS) of a graph rely on?

Accepted Answer

Queue

Answer

BFS explores vertices level by level, using a FIFO queue to process nodes in discovery order.

Question 3

What is the primary drawback of open addressing with linear probing in hash tables?

Accepted Answer

Primary clustering degrades performance as the table fills

Answer

Linear probing causes runs of occupied slots (primary clustering), lengthening probe sequences as load increases.

Question 4

Inserting a new element into a binary min-heap of n elements takes how long in the worst case?

Accepted Answer

O(log n)

Answer

The new element is placed at the bottom and bubbles up at most the height of the heap, which is O(log n).

Question 5

Which scenario is a classic use case for a trie (prefix tree)?

Accepted Answer

Autocomplete suggestions for typed prefixes

Answer

A trie stores strings by shared prefixes, making prefix-based lookups like autocomplete very efficient.

Data Structures Practice Test