Maths question on using the minimum amount of DVD disc

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Discussion Overview

The discussion revolves around the problem of efficiently burning 14 files onto the minimum number of DVD5 discs, each with a capacity of approximately 4.37GB. Participants explore strategies for file arrangement to optimize space usage, touching on concepts related to packing and the bin packing problem.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant suggests starting with the largest file and filling the remaining space with the largest possible additional file, iterating this process to maximize disk usage.
  • Another participant notes that several files exceed half the DVD's capacity, indicating that at least some files cannot be paired on the same disc, which influences the minimum number of discs required.
  • A different perspective introduces the concept of the bin packing problem, suggesting that for a small number of files, a brute force approach could be effective.
  • One participant proposes using compression software that allows splitting files across multiple discs, potentially improving space utilization.

Areas of Agreement / Disagreement

Participants express differing views on the best approach to minimize the number of discs. While some agree on the importance of starting with the largest files, others highlight constraints based on file sizes that complicate the packing process. The discussion remains unresolved regarding the optimal arrangement and the exact number of discs needed.

Contextual Notes

Participants acknowledge the complexity of the problem, including the need to check if all files can fit within the proposed number of discs and the implications of file sizes on packing strategies.

kenny1999
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this is a practical question

I have 14 files to burn on a single layer DVD5 disc in which each of them has a size approximately 4.37GB

Those 14 files are of the size (in GB)

2.25
2.25
1.15
3.05
1.16
2.40
0.65
2.05
1.36
1.97
1.11
1.14
2.48
2.65

All values are in GB

If I want to burn these 14 files into minimum number of DVD discs for environmental and economic purposes, how should these files be arranged? I think at least a few discs could be saved if the files are arranged correctly, and I want to learn the concept. thanks
 
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Basically you want to pack each disk as much as possible. You could figure it out like this. Start with your largest file and burn it on a disk. Then you'll have 4.37-3.05=1.32 space. There is not enough room for the two smallest files to fit on that disk, so just put the largest file on their with less than 1.32. In other words, the 1.16. So your first disk is
(3.05, 1.16).
Cross those off your list and continue this process. Next step you load
(2.65, 1.36), so cross those off the list.
Then you load 2.48 and notice you have 1.89 space left. Your largest available file is 1.15 which leaves you enough room to squeeze on the .65, so you got
(2.48, 1.15, .65)
Next
(2.40, 1.97) an exact fillup. Hopefully that one actually fits :)
You could probably figure out the last five.

Now you only have 7 left...
 
Vargo said:
Basically you want to pack each disk as much as possible. You could figure it out like this. Start with your largest file and burn it on a disk. Then you'll have 4.37-3.05=1.32 space. There is not enough room for the two smallest files to fit on that disk, so just put the largest file on their with less than 1.32. In other words, the 1.16. So your first disk is
(3.05, 1.16).
Cross those off your list and continue this process. Next step you load
(2.65, 1.36), so cross those off the list.
Then you load 2.48 and notice you have 1.89 space left. Your largest available file is 1.15 which leaves you enough room to squeeze on the .65, so you got
(2.48, 1.15, .65)
Next
(2.40, 1.97) an exact fillup. Hopefully that one actually fits :)
You could probably figure out the last five.

Now you only have 7 left...

Thanks i ll try
 
Several of the files are bigger than half the size of the DVD.

You con't fit two of those files onto the same DVD, so that gives you the minimum possible number of disks.

You then need to check that you can actually fit all the files onto that many disks.
 
Your task is what's called the bin packing problem. For such a small number of files, any brute force approach probably will be satisfactory. Another possibility: If you don't need to store the files in their native format, most compression programs will allow you to split the files across multiple discs. That feature allows you to fill up each disc before going to the next one.
 

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