- cross-posted to:
- programmer_humor@programming.dev
- cross-posted to:
- programmer_humor@programming.dev
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Step 4 seems to do nothing?
Step 4 splits the pair above into single elements, from step 5 on the groups are getting merged.
How does the last step sort an of the sizes? Why even have all the other steps if that one can do it all?
The one and only way to learn sorting algorithms: https://youtu.be/dENca26N6V4
When you merge two sorted lists, you only have to compare the first element of each, since you can trust that all of the other elements are bigger. All the steps before that are there to make sure that is true.
Wait, how do I know that all four of the right half aren’t smaller than all four of the Left half?
It doesn’t matter. You check the first of each group and pick the smallest, then compare the one you didn’t pick with the next one of the other group. In your example, you would pick all of the ones from the right side and once it is empty, just add all the ones on the left.
You don’t, and they can be.
Watch the animation on Wikipedia: https://en.wikipedia.org/wiki/Merge_sort
