Data Structures & Algorithms

A ____ follows last-in, first-out (LIFO) order.

• array
• queue
• tree
• stack

Which data structure follows FIFO order?

• Hash table
• Queue
• Stack
• Graph

What is the time complexity of binary search?

• O(n²)
• O(1)
• O(n)
• O(log n)

____ store elements in contiguous memory for constant-time index access.

• Arrays
• Stacks
• Linked lists
• Graphs

BFS uses a queue and explores level by level.

• True
• False

DFS uses a queue to explore as deeply as possible.

• True
• False

What complexity is typical of merge sort and quicksort?

• O(n log n)
• O(1)
• O(log n)
• O(n²)

____ stores results of subproblems to avoid repeating work.

• Greedy
• Dynamic programming
• Hashing
• Recursion

Which pattern tracks a range of elements for substring problems?

• Two-pointer
• Sliding window
• Greedy
• Recursion

Greedy algorithms make the locally best choice at each step.

• True
• False

What do hash tables provide on average?

• Constant-time lookup
• Sorted order
• LIFO order
• Level-by-level access

A loop running one time too many is called an ____ error.

• recursion
• off-by-one
• null
• overflow

O(2ⁿ) represents exponential time complexity.

• True
• False

Which structure models networks of connected nodes?

• Stacks
• Graphs
• Arrays
• Queues

What underlies divide-and-conquer strategies like merge sort?

• Recursion
• Two-pointer
• Greedy
• Hashing