Data Structures Arrays and Strings

Question 1

What is the time complexity of accessing an element in an array by index?

Accepted Answer

O(1)

Answer

O(n)

Answer

O(log n)

Answer

O(n²)

Question 2

Which array traversal technique uses two pointers moving toward each other from both ends?

Accepted Answer

Two-pointer technique

Answer

Sliding window

Answer

Binary search

Answer

Divide and conquer

Question 3

What is the worst-case time complexity of searching for an element in an unsorted array?

Accepted Answer

O(n)

Answer

O(1)

Answer

O(log n)

Answer

O(n log n)

Question 4

Which operation is most expensive in a dynamic array when it needs to resize?

Accepted Answer

Appending when capacity is full

Answer

Reading an element

Answer

Accessing the last element

Answer

Checking the length

Question 5

What does the sliding window technique optimize when processing subarrays or substrings?

Accepted Answer

Avoiding nested loops by reusing previous computations

Answer

Sorting the array

Answer

Reversing the array in place

Answer

Finding the median element

Question 6

In a 2D array stored in row-major order, which access pattern is more cache-friendly?

Accepted Answer

Row-by-row access

Answer

Column-by-column access

Answer

Random access

Answer

Diagonal access