CS fundamentals and algorithms

Sorting and Swift sort

Can you compare merge sort and quicksort: how each works, and their time and space complexity?

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Merge sort is always O(n log n) with O(n) extra memory and stable; quicksort is O(n log n) on average, O(n²) worst case, in place, and unstable. Since Swift 5, sort() is a stable sort (Timsort family), documented as guaranteed only from 2023.

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Sorting and Swift sort

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