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# D1 (Decision 1) 17 May 2013 Official Thread Watch

1. I tend to use this guy's method for the quick sort.

2. Omg I hate bubble sort it literally takes me like 10 minutes to do that crap which I can do in my head in like 10 secs.
3. (Original post by posthumus)
I personally do circles around the chosen pivot... & then after I'm done with it, I put a box around it... to show it's been used I find it the most convenient way.
thanks and a quick question in route inspection always the parts b , where it says this person will start at this point x and finishes at any point e..tc.

for this question do you just look at which arcs are the shortest and state repeat and add to the total length but how do u where it should end?
4. (Original post by Better)
Fortitude one last question.

What is the definition of a Graph ironically it's the only definition I'm confused about now.

2009 Papers are odd. I just want to get it confirmed.
Hi again, well I read that it consists of points (vertices or nodes) that are connected by lines (edges or arcs). 2009 papers are probably odd because they were the first ones in our spec.
5. (Original post by otrivine)
thanks and a quick question in route inspection always the parts b , where it says this person will start at this point x and finishes at any point e..tc.

for this question do you just look at which arcs are the shortest and state repeat and add to the total length but how do u where it should end?
Usually in these type of questions there are 4 nodes with odd valencies. You pick the 2 that will give you the shortest path then the other 2 nodes will be your start & finish (doesn't matter which way around)
6. Anything useful on graph theory (I'm on AQA )?
7. (Original post by posthumus)
Usually in these type of questions there are 4 nodes with odd valencies. You pick the 2 that will give you the shortest path then the other 2 nodes will be your start & finish (doesn't matter which way around)
what happens if they gave u the start and finish node. thanks
8. (Original post by otrivine)
what happens if they gave u the start and finish node. thanks
Wouldn't you then just pick the corresponding nodes then? E if you have
AC + FD
AF + CD
& they told you to start at C & end at D I think you'd probably have to then repeat AF, right? Don't think I've seen a question like that before
9. Oh guys, I've seen this Q come up a few times which says if for eg 2 routes should be included (in route inspection) in the spanning tree explain which algorithm you'd use to complete the tree & how it should be adapted so how do you know whether it'll be Prim's or Kruskal's?
10. (Original post by Anythingoo1)
As a common law in exams, what you've studied extensively right down to the last word = Not in the exam at all

What you aren't too confident on = 6 mark question

OH GOD THE DEFINITIONS, WHY THE DEFINITIONS
Haha that is so true. Im more worried about not having enough time than anything really The worse thing is that the definitions barely make any sense to me. Good luck for friday
11. Anyone know how to use a cascade/gantt chart to determine a lower bound for the number of workers needed?

Specifically in this question

Yes, I will use a ruler in the proper exam ignore the messiness!

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12. (Original post by Westeros)
Anyone know how to use a cascade/gantt chart to determine a lower bound for the number of workers needed?

Specifically in this question

Yes, I will use a ruler in the proper exam ignore the messiness!

Posted from TSR Mobile
You don't need to

Just find the amount of time all tasks will take

then divide by the time allocated for the project... which looking at your gantt chart I assume it 22

& I think it's pretty neat
13. (Original post by Westeros)
Anyone know how to use a cascade/gantt chart to determine a lower bound for the number of workers needed?

Specifically in this question

Yes, I will use a ruler in the proper exam ignore the messiness!

Posted from TSR Mobile
If it says to find the lower bound using the diagram you need to find a time on the chart where there will be the most clashes, for example, I'd look at time 11-12 where I think 4 tasks clash and cannot be moved to remove the clash. Therefore 4 workers must work at that time and therefore the lower bound is 4...I think

EDIT: I know it would be tempting just to use the formula for this one, but I've seen the method I've stated above in several mark schemes.
14. (Original post by Westeros)
Anyone know how to use a cascade/gantt chart to determine a lower bound for the number of workers needed?

Specifically in this question

Yes, I will use a ruler in the proper exam ignore the messiness!

Posted from TSR Mobile
Lower bound = Sum of all activities/time for critical activities
= 59/22 = 3 when rounded up.
15. (Original post by RobertHM)
If it says to find the lower bound using the diagram you need to find a time on the chart where there will be the most clashes, for example, I'd look at time 11-12 where I think 4 tasks clash and cannot be moved to remove the clash. Therefore 4 workers must work at that time and therefore the lower bound is 4...I think

EDIT: I know it would be tempting just to use the formula for this one, but I've seen the method I

've stated above in several mark schemes.
Yes I got a lower bound of 4 as well
16. (Original post by Dilzo999)
Lower bound = Sum of all activities/time for critical activities
= 59/22 = 3 when rounded up.
It should be 4
17. (Original post by Westeros)
Anyone know how to use a cascade/gantt chart to determine a lower bound for the number of workers needed?

Specifically in this question

Yes, I will use a ruler in the proper exam ignore the messiness!

Posted from TSR Mobile
What does the mark scheme say? I've actually scheduled it and you can see in one line there's going to be all critical activities, then another worker has A,D,I,K another has B,F and one last worker has G. Which = 4 workers so I don't know what that formula is about.
18. (Original post by Dilzo999)
Lower bound = Sum of all activities/time for critical activities
= 59/22 = 3 when rounded up.
Hi

with lower bounds if you get 2.01 do you round to 3 ? thanks
19. I got 2.6989898 something not 2.01. THIS IS CONFUSING XD.

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