Lesson 117
Sorting Algorithm Comparison
Choosing the Right Sort
1:00How to choose the right sorting algorithm by comparing time complexity, stability, and memory across Insertion, Merge, Heap, and Quick Sort — plus the O(n log n) lower bound and the hybrids real languages ship.
By the end, you can
- Identify which sorting algorithms belong to the O(n²) class and which to the O(n log n) class.
- Explain the decision-tree lower bound proof and state the Ω(n log n) wall it establishes.
- Define stability and explain why it matters for multi-key sorting.
- Compare Merge, Heap, and Quick Sort by worst-case time and extra memory.
- Describe when Quick Sort degrades to O(n²) and name two strategies to prevent it.
- Explain how Timsort and Introsort combine multiple sorting algorithms to get the best of each.
- Apply the pick-by-constraint decision guide to select the right sort for a given scenario.
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