d1 bubble sort, please help! Watch

zomgleh
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#1
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here's the link:
http://tinypic.com/view.php?pic=2lbf18o&s=6

I believe there's a mistake:

the 3rd row is the 2nd pass, I believe the 3rd pass is incorrectly written.

Correct me if I'm wrong?
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zomgleh
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also,
anyone who has done the examination style paper from the text book (d1 edexcel),
do you know if number 3 b- the first-fit bin packing, has the wrong answer?
I got a different setting of the bins?
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Clarity Incognito
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(Original post by zomgleh)
here's the link:
http://tinypic.com/view.php?pic=2lbf18o&s=6

I believe there's a mistake:

the 3rd row is the 2nd pass, I believe the 3rd pass is incorrectly written.

Correct me if I'm wrong?
The bubble sort solution is correct.

Don't have the book for your second enquiry, post the question.
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zomgleh
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(Original post by Clarity Incognito)
The bubble sort solution is correct.

Don't have the book for your second enquiry, post the question.
here you go:
http://tinypic.com/view.php?pic=r7oxzt&s=6
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zomgleh
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(Original post by Clarity Incognito)
The bubble sort solution is correct.

Don't have the book for your second enquiry, post the question.
H L R A T J Y S M

H L A R J T S M Y

H A L J R S M T Y

A H L J R M S T Y

A H J L M R S T Y
why wont the bold part be-

A H J L R M S T Y ??
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Clarity Incognito
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(Original post by zomgleh)
here you go:
http://tinypic.com/view.php?pic=r7oxzt&s=6
Sorry to say but that's correct as well, the first-fit algorithm is stated as follows:

Taking the boxes in the order listed, place the next box to be packed in the first available bin that can take that box.
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Clarity Incognito
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(Original post by zomgleh)
H L R A T J Y S M

H L A R J T S M Y

H A L J R S M T Y

A H L J R M S T Y

A H J L M R S T Y
why wont the bold part be-

A H J L R M S T Y ??
I only checked up to the second pass because I misread. Anyway, yeah it should be A H J L R M S T Y

not A H L J R M S T Y

EDIT: The bin one is definitely correct though, I went and actually did it.
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zomgleh
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(Original post by Clarity Incognito)
I only checked up to the second pass because I misread. Anyway, yeah it should be A H J L R M S T Y

not A H L J R M S T Y

EDIT: The bin one is definitely correct though, I went and actually did it.
cool,
thanks.
do you know where I can find the jan 2010 mark scheme btw?
edexcel d1?
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Clarity Incognito
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(Original post by zomgleh)
cool,
thanks.
do you know where I can find the jan 2010 mark scheme btw?
edexcel d1?
No worries, and sorry I don't, try and post a request in the 'maths exams' forum, you might catch more luck.
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jaz_jaz
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(Original post by zomgleh)
cool,
thanks.
do you know where I can find the jan 2010 mark scheme btw?
edexcel d1?
hey let me know if you get that, i'm doing D1 alone (no teachers to help me or anything )
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zomgleh
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(Original post by jaz_jaz)
hey let me know if you get that, i'm doing D1 alone (no teachers to help me or anything )
same here, good luck!
and here's the MS
http://www.scribd.com/doc/29694745/E...Marking-Scheme
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jaz_jaz
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(Original post by zomgleh)
same here, good luck!
and here's the MS
http://www.scribd.com/doc/29694745/E...Marking-Scheme
do you happen to have the question paper?
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zomgleh
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(Original post by Clarity Incognito)
I only checked up to the second pass because I misread. Anyway, yeah it should be A H J L R M S T Y

not A H L J R M S T Y

EDIT: The bin one is definitely correct though, I went and actually did it.
aha i get it now, thanks.
also, could you please take a look at this:

http://tinypic.com/view.php?pic=15ochw2&s=6

i don't think it's correct, i know for a fact there are many mistakes in the new edition of the d1 book.
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zomgleh
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(Original post by jaz_jaz)
do you happen to have the question paper?

here: http://www.srepapmaxeeeerf.org/A%20L...nuary_2010.pdf


do you know if this is correct?
http://tinypic.com/view.php?pic=15ochw2&s=6
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Clarity Incognito
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(Original post by zomgleh)
aha i get it now, thanks.
also, could you please take a look at this:

http://tinypic.com/view.php?pic=15ochw2&s=6

i don't think it's correct, i know for a fact there are many mistakes in the new edition of the d1 book.
What's wrong with it?

C must be happening and even though D has some float. D must be started in the region of day 3 to day 9 and lasts for 6 days, therefore D must be happening on day 8.

Activity F must be happening, whilst E and G may be happening.
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zomgleh
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also, do the numbers in the tiny circles (event) in the activity network matter?
I mean, does the order of numbering matter?
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zomgleh
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(Original post by Clarity Incognito)
What's wrong with it?

C must be happening and even though D has some float. D must be started in the region of day 3 to day 9 and lasts for 6 days, therefore D must be happening on day 8.

Activity F must be happening, whilst E and G may be happening.

sorry but, for part b- how can the activities E and G be classified as - may be happening- on the 15th day? if you trace down the vertical line, E and G are both at their "float" stage on the 15th day, doesn't that mean they must be happening?
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Clarity Incognito
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(Original post by zomgleh)
sorry but, for part b- how can the activities E and G be classified as - may be happening- on the 15th day? if you trace down the vertical line, E and G are both at their "float" stage on the 15th day, doesn't that mean they must be happening?
Yes, the order of the nodes in an activity network matter, allows you to work out  l_i for each node and is required for finding the critical path.

E and G may not be happening on the 15th day. Just because the float covers the 15th day, it doesn't mean that they are happening then. They can be started at their earliest start times and therefore they are finished before day 15.
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zomgleh
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(Original post by Clarity Incognito)
Yes, the order of the nodes in an activity network matter, allows you to work out  l_i for each node and is required for finding the critical path.

E and G may not be happening on the 15th day. Just because the float covers the 15th day, it doesn't mean that they are happening then. They can be started at their earliest start times and therefore they are finished before day 15.

so why is it that activity 6 doesn't HAVE to or must not be happening on day 8?

and do you agree with this-
http://tinypic.com/view.php?pic=m9x6hz&s=6

*sorry i know i have too many questions, thanks for your time!*
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Clarity Incognito
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(Original post by zomgleh)
so why is it that activity 6 doesn't HAVE to or must not be happening on day 8?

and do you agree with this-
http://tinypic.com/view.php?pic=m9x6hz&s=6

*sorry i know i have too many questions, thanks for your time!*
Activity 6?

If you're asking whether I agree with the yellow boxes, I do but the one talking about activity F is hidden from view so I can't confirm that one.

*No worries *

EDIT: Answers for question 1 should be:

a) C and E
b) I and J
c) F, H and I
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