Questions
29 of 29
1Explain the difference between an in-place algorithm and an out-of-place algorithm.
2What are the risks of using Recursion? (Stack Overflow, Exponential Time)
3Explain the difference between a Data Structure and an Abstract Data Type (ADT).
4What is Time Complexity? How is it different from Space Complexity?
5What is Amortized Analysis? When is it used? (Hint: Dynamic Arrays)
6Explain Big-O notation. What do O(1), O(n), O(log n), O(n log n), O(n²) mean?
7Rank the common Big-O complexities from best to worst.
8Explain Memoization. How does it optimize recursive solutions?
9What is the difference between Best Case, Average Case, and Worst Case complexity?
10What is Recursion? How does it relate to the Call Stack?
11What are the risks of using Recursion? (Stack Overflow, Exponential Time)
12Explain the difference between an in-place algorithm and an out-of-place algorithm.
13Explain Memoization. How does it optimize recursive solutions?
14What is Amortized Analysis? When is it used? (Hint: Dynamic Arrays)
15Explain Big-O notation. What does O(1), O(n), O(log n), O(n log n), O(n^2) mean?
16Explain the difference between a Data Structure and an Abstract Data Type (ADT).
17What is Time Complexity? How is it different from Space Complexity?
18Rank the common Big-O complexities from best to worst.
19What is the difference between Static and Dynamic Data Structures?
20What is Recursion? How does it relate to the Call Stack?
21What is the Master Theorem? When can it be applied?
22What is the difference between Static and Dynamic Data Structures?
23What is the Master Theorem? When can it be applied?
24What is the difference between Best Case, Average Case, and Worst Case complexity?
25What is the difference between Linear Data Structures and Non-Linear Data Structures?
26What is a stable algorithm? Why does stability matter in sorting?
27What is the difference between Linear Data Structures and Non-Linear Data Structures?
28What is a Data Structure? Why do we need them?
29What is a stable algorithm? Why does stability matter in sorting?
Data-StructuresData-Structures
Basics
Complexity Analysis
Arrays and Strings
Linked Lists
Stacks and Queues
Hash Tables
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What is a stable algorithm? Why does stability matter in sorting?

Stability in Sorting Algorithms

  1. 1

    Stable sorting algorithms: Merge Sort, Insertion Sort, Bubble Sort, Timsort

  2. 2

    Unstable sorting algorithms: Quick Sort (typical implementation), Heap Sort, Selection Sort

  3. 3

    Stability is essential for multi-key sorting (sort by key A, then stably by key B)

  4. 4

    Some unstable algorithms can be made stable by adding index-based tie-breaking, at the cost of extra memory

Difficulty: 5/10

Follow-up Questions

  • ❓How would you make Quick Sort stable, and what would the cost be?
  • ❓Why is Timsort (Python/Java's default sort) designed to be stable?