Merge Sort Flashcards

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Look through all the flashcards to see what's on both sides.
Make sure you understand the information on each card. If something's unclear, click the link to the revision notes at the bottom of the page for more details.

2️⃣ Test yourself:

Look at the question or prompt on each card and try to remember the answer before flipping it over.
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Note: We may include questions that have multiple correct answers. It's useful to remember specific examples to understand these concepts better.

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What is merge sort?

A sorting algorithm that splits a list and then merges it in order.

Split the list into halves, then merge the sublists in order.

When each sublist has one item. A single item is already sorted.

Compare the first items. Move the smaller into a new list. Repeat until both lists are empty.

Copy all the remaining items from the other sublist into the new list.

Divide and conquer: split the list, sort parts, then join them.

No. It needs extra memory about the size of the list.

Yes. Equal items keep their original order.

O(n log n) in the best, average, and worst cases.

Yes. It calls itself to sort each half of the list.

No. It splits and merges in the same pattern each time.

Any data you can compare, such as numbers or strings.