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

Original post by Xyonzz

basically if you've already done one matching, and they tell you to do the algorithm again to get a final complete matching, i'd recommend drawing out your new initial matching you made. From there you'll only have one unmatched node, so start from there and everything should be complete! but remember some points wont be changed, so to be safe when you rewrite them on write 'unchanged' next to it, just to be safe

right so u mean that when we find the maximum and we get those letters the when they say find improve matching do we draw our letters in the new graph ?

Reply 263

The Illuminati

4

Original post by otrivine

right and for feassilbe region how can we find out that region once i have drawn all my lines?

Its the bit that's enclosed by all your lines. I don't know how to explain it better.....

Reply 264

Xyonzz

Original post by otrivine

right so u mean that when we find the maximum and we get those letters the when they say find improve matching do we draw our letters in the new graph ?

not 100% sure i know what you mean. If they ask you to apply the algorithm, then they ask you a second time to get a complete matching, you'd act like the one you found in the previous part is the initial matching, and get a complete one from there. after you write out the string of letters/numbers 'change status' and write out all of them separately i.e.: A = 5, B = 4, C = 3, etc

Reply 265

otrivine

Original post by The Illuminati

Its the bit that's enclosed by all your lines. I don't know how to explain it better.....

i got it thanks do u think this will be an easy paper with high grade boundaries?

Reply 266

JenniS

2

when you have to fill in a table from a flow chart question, how important is which row you put things in because sometimes my table looks different to the mark scheme even if i get the correct answer?

Reply 267

puma21

Original post by otrivine

i got it thanks do u think this will be an easy paper with high grade boundaries?

D1 usually has highish grade boundaries and higher in January.

Reply 268

The Illuminati

4

Original post by otrivine

i got it thanks do u think this will be an easy paper with high grade boundaries?

Not a lot of people take D1 and the ones that do, I hunk most take it in June so grade boundaries will probably be higher in January.

Reply 269

When doing bubble sort, you dont actually have to put a ring around each two you are swapping do you? Just a line under the last number or letter to show thats now in it correct place?

Reply 270

Xyonzz

Original post by bethany18

When doing bubble sort, you dont actually have to put a ring around each two you are swapping do you? Just a line under the last number or letter to show thats now in it correct place?

to be safe i'd use a ring/bubble for each one, until you've made one complete pass.
Then when you do it again you just write 'Pass 2' and write them out, 'Pass 3' underneath and write it out and so on, as long as theyve seen on the first pass that you're doing it properly should be fine, and it only takes a minute or so :rolleyes:

Reply 271

DavidCrow

If scheduling comes up then I'm ****ed
If scheduling doesn't come up then I'm not :smile:

(unless I make stupid mistakes)
Good luck to everyone for this afternoon!

Reply 272

Original post by Xyonzz

to be safe i'd use a ring/bubble for each one, until you've made one complete pass.
Then when you do it again you just write 'Pass 2' and write them out, 'Pass 3' underneath and write it out and so on, as long as theyve seen on the first pass that you're doing it properly should be fine, and it only takes a minute or so :rolleyes:

Thank you, full bin packing is when you sort of match them up yourself to get the most full bins really isnt it?

Reply 273

DavidCrow

Original post by bethany18

Thank you, full bin packing is when you sort of match them up yourself to get the most full bins really isnt it?

Yeah but you also have to remember that once you've got all the full bins possible you order the remaining using first fit

Reply 274

whatever_x

Ahh I'm so nervous :frown:

I really hate the whole of the linear programming chapter...
What are the chances of it coming up?

Reply 275

otrivine

Original post by DavidCrow

Yeah but you also have to remember that once you've got all the full bins possible you order the remaining using first fit

for these bin packings are there always alternative answers?

Reply 276

Original post by whatever_x

Ahh I'm so nervous :frown:

I really hate the whole of the linear programming chapter...
What are the chances of it coming up?

Me too but i'd say its a 90% chance really they always have a question on linear programming i think, i really hope this ones the exception and doesnt have it on ha

Reply 277

ms93

I hate drawing an activity network from a precedence table :frown:

I hope that doesn't come up!! Knowing my luck it will!

Reply 278

Quantus Life

How do you decide which vertex to start from on an initial matching? Sometimes there are two free on the left side and it's not always obvious which one to start from

Reply 279