Data Structures in computer-science : Practice MCQ Questions & Answers with Explanations

2 practice sets · Page 1 of 1

Computer ScienceHardData StructuresSorting

What is the worst-case time complexity of Quick Sort?

O(n log n)

O(n)

O(n²)

O(log n)

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Correct Answer: C — O(n²)

Explanation:

Quick Sort's worst case O(n²) occurs when the pivot is always the smallest or largest element (e.g., already sorted array with first element as pivot). Average case is O(n log n).

Computer ScienceEasyData StructuresArrays

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

O(n)

O(log n)

O(1)

O(n²)

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Correct Answer: C — O(1)

Explanation:

Arrays support direct index-based access. The memory address is calculated as base_address + index × element_size, making it O(1).