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AQA D1 - minimum spanning trees - Prims

If you are given a two way table of connections between nodes but not told which node to start at is it possible to get different values for the spanning tree depending where you start?

I would think that you wouldn't but I have a different answer to the book but the book has started at a different node to me.
Original post by maggiehodgson
If you are given a two way table of connections between nodes but not told which node to start at is it possible to get different values for the spanning tree depending where you start?

I would think that you wouldn't but I have a different answer to the book but the book has started at a different node to me.


If there's more than one possible minimum spanning tree then, yes, you could get a different answer.

Does your tree have the same weight as the book's answer. If so, fine. Else....
Original post by ghostwalker
If there's more than one possible minimum spanning tree then, yes, you could get a different answer.

Does your tree have the same weight as the book's answer. If so, fine. Else....


No. It doesn't and that's a worry. Hence my question.

Here is the question (question 8)

Scan0004.pdf

And here's my working

Oops. At this point, in writing it all out more neatly for posting, after doing it 3 times before contacting TSR, I've spotted my problem. I'm number blind.

So, basically, it doesn't matter where you start you will always get the same value of MST but not necessarily the same "shape"?
Original post by maggiehodgson
No. It doesn't and that's a worry. Hence my question.

Here is the question (question 8)

Scan0004.pdf

And here's my working

Oops. At this point, in writing it all out more neatly for posting, after doing it 3 times before contacting TSR, I've spotted my problem. I'm number blind.

So, basically, it doesn't matter where you start you will always get the same value of MST but not necessarily the same "shape"?


Yes, and this usually happens if you have two edges of equal weight
Original post by maggiehodgson

So, basically, it doesn't matter where you start you will always get the same value of MST but not necessarily the same "shape"?


Correct - as sarcastic-sal said.
Thanks everybody.

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