CodeSignal Technical Assessment Sorting and Searching Algorithms Questions and Answers

Question 1

A developer needs to search for an element within a large, sorted array of one million integers. Which algorithm offers the best worst-case time complexity for this task?

Accepted Answer

Binary Search

Answer

Linear Search

Answer

Merge Sort

Answer

Quick Sort

Question 2

You are tasked with sorting a list of customer objects based on their purchase date. If two customers have the same purchase date, their original relative order must be preserved. Which of the following sorting algorithms is most suitable for this requirement?

Accepted Answer

Merge Sort

Answer

Heap Sort

Answer

Quick Sort

Answer

Selection Sort

Question 3

What is the worst-case time complexity of the Quick Sort algorithm, and under what condition does it typically occur?

Accepted Answer

O(n^2), when the input array is already sorted and the pivot is chosen as the first or last element.

Answer

O(n log n), when the pivot elements consistently divide the array into two halves of nearly equal size.

Answer

O(n), when the input array is completely random.

Answer

O(log n), when the input array contains many duplicate elements.

Question 4

A programmer is working on a memory-constrained embedded system and needs to sort an array of sensor readings in-place. Which of the following sorting algorithms has the best auxiliary space complexity for this task?

Accepted Answer

Heap Sort

Answer

Merge Sort

Answer

Radix Sort

Answer

Tim Sort

Question 5

Under which of the following conditions would Insertion Sort likely outperform Quick Sort?

Accepted Answer

When the dataset is small or nearly sorted.

Answer

When sorting a very large, randomly ordered dataset.

Answer

When the dataset contains many floating-point numbers.

Answer

When a stable sort is not required.

Question 6

Which of the following is a fundamental prerequisite for the Binary Search algorithm to function correctly?

Accepted Answer

The array must be sorted.

Answer

The array must not contain any duplicate values.

Answer

The array must have a length that is a power of two.

Answer

The array must only contain positive integers.