The Edexcel D1 (18/05/12 - AM) Revision Thread

Hey arsey, what time are you planning to post the solutions on Saturday?

I don't wanna see prims algorithm in the test
the rest WILL come up

when I wake up

Hey everyone! Can someone help with explaining Q5c on the Jan 2011 paper please? I always struggle with this sort of question on the paper. Thanks in advance

what is wrong with Prims, it is very easy to apply???

I think Prims and Bin packing are nailed on to be on tomorrow.

Just done this paper.

The question states the machine will start at D, and you can finish at any other odd node. What I do first is find the shortest lengths between the other three nodes - so (F-I), (A-f), and (A-I), and then base where I will end on the node that isn't one of the two where you will add a repeat arc.

So in the case of this question you would identify that (FHI) is the smallest repeat arc, (5.3), and therefore would choose to finish at A, as this would minimise the length of the journey.

Hope that makes some sense and helps.

When doing binary search which part do you reject if the person is not on the list?

I can do it but it requires more thought for me, I prefer kruskal.


Question: when I do kruskals and there are 3 arcs that has to be rejrcted at the end, the MS doesnt include them, why not

With Prim's algorithm and the distance matrix, when you're saying which edges you select, say, you choose C connected to F, does it matter whether you write CF or FC (I know this is very trivial, but I don't want to lose marks!)

Thanks!

because prim's stops once the/a MST has been found

Cheers that really helped Awgh I hate D1 so much! Cannot revise it at all

How do you know when to stop though?
I don't understand, I'm talking about kruskal's, not prims

once every node has been connected, applies to both Kruskal's and Prim's

ohhhhhhh, thanks, i get it now.

Would I lose marks if I still carried on?