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I'm in need of an implementation of a decision tree algorithm. I checked this, ID3 Decision Tree Algorithm in C#[^] , but the comments are in some other language and I really can't understand it.
I managed to get code for "drawing" the decision tree, it's in Java by the way, I need to know how to use it to get results from my own data. Or if possible the full implementation of this, i.e. I should be able to train the tree and then enter new data and get the result.
I searched in Google and stuff but did not get a proper code sample.
btw: I need this in either VB, Java or any .Net language.
Thanks.
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Enter two integers n and m, from the series 1,2,3 ....... n ,get a few numbers at random, it is equal to m, called for all possible combinations of them
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can you form a few seperated sentences? Or explain what you really want to do?
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sorry! my English is very poor!
"input two interger n and m, from the serious number 1, 2, 3....n, take out fews integers and make it is equal to m,list all possible combinations"
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I feel what he wants is to input two numbers n and m and the program should choose some numbers from series 1,2..n whose sum equals m and return all such combinations.
For n=10, m=8, the possible combinations are:
1+7
2+6
3+5
..
1+1+6
1+2+5
..
..
there can be a lot of such combinations.
This is probably the ideal candidate for DP?
1. store all possible ways to make 1 using numbers from given series and store them
2. likewise all possible ways to make 2. since 2 can only be either using it alone or 1+1 and then to make 1, you already have ways stored during step 1 and so on for oher nos. for 3 = 3, 2+1. use info. for ways to make 2 and you'll automatically get 3, 2+1, 1+1+1
for 4 = 4, 3+1...
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Subset Sum problem
I am pasting an algorithm, got this from a book
Algorithm SumOfSubSet(s,k,r)
{
x[k] := 1;
if( s + w[k] = m ) then Write( x[1:k]);
else if( s + w[k] + w[k+1] <= m )
then SumOfSub( s + w[k], k+1, r-w[k]);
if( (s+r-w[k] >= m) and (s + w[k+1] <= m )) then
{
x[k] := 0;
SumOfSub( s, k + 1, r - w[k]);
}
}
s = is the sum to be generated
w is the set with size n ,
x is an array and if x[i] is one means <code> ith element in w is in the subset
k is the index of element in w we are examining
r is the remaining sum that can be created from k +1 th element to n th item in w
modified on Thursday, May 12, 2011 9:23 AM
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Pleaze i need a help , i need an implementation for the subset sum problem using these algorithms
1. An exponential time exact algorithm
2. Fully polynomial-time approximation scheme
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Hello people!
I am looking for a way to simulate movement of units along a path, i mean as you can see it in strategy games. The path consists of waypoints and i am looking for a method to make the units follow these with a somewhat life-like way, so no too sharp turns, try to evade collision with other units and so on. I tried to google it up but i am probably not using the correct search terms because i didn't find anything usefull really, so i thought i ask here, maybe you folks have the know-how, or at least know where or what i should look for.
Thanks in advance.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <
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Thank you.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <
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If you have the paths worked out (perhaps using some of the techniques shown in the very good selection of links posted above) then you might also be interested in steering behaviours - route following, collision avoidance, queuing, flocking etc. :-
http://www.red3d.com/cwr/steer/[^]
Days spent at sea are not deducted from one's alloted span - Phoenician proverb
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Indeed i am, thank you for the help.
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <
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I have little discrete spaces but they are non-Euclidean. May I still call them manifolds?
Tadeusz Westawic
An ounce of Clever is worth a pound of Experience.
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I need some help as I am finding it hard to create a program that can make character shapes such as a triangle in a console application (C#):
*
***
*****
*******
As an example of what I would like to print, i.e. I want the triangle's height 4 and my program will draw a triangle as described.
This is so that I can improve on control structures, squares and rectangles are easy
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Total number of characters? Total number of stars? Total number of spaces? Half total number of spaces? Increment values? etc ...
It's time for a new signature.
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Basically the way to approach this is to draw a rectangle like you did before but put some conditions in to determine if you should print a star or a blank.
First to get the width: Notice that except for the top line the triangle's width increases by 2 for each line it goes down.
Therefore: Width = (Height * 2) - 1
To determine whether to draw a star you need to find if you are close enough to the center of the triangle.
Center = Width / 2
On each line the triangle gets one wider in each direction so you need 2 variables to hold the range where stars should be drawn. So if you use Min and Max as your variable the should initally be set to Center and then subtract 1 from min each line you go down and add 1 to max each line you go down. You can then use these variable to test if your loop counter is between these 2 variables.
Hope this helps,
Mike
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All,
I'm in need of an algorithm that I have no idea about comparing it to other algorithms.
Imagine if you had a set of wooden blocks, all the same thickness but differing in lengths. The goal is to stack all of the blocks in such a way that the total length of this "wall" is the shortest length possible. There would be a different result depending on if you stack the wall 2, 3, 4, or N blocks high.
The wall doesn't have to be perfectly straight on both sides either.
Not sure what this is even similar to, and would appreciate some guidance.
I'd also appreciate knowing where some of you look for information about algs, because it seems like I can never find a comprehensive site containing the names, applications and descriptions of common or more obscure ones. If any of you want to give up your sources, your secrets are moderately safe with me
Thanks,
Michael Fritzius
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your problem seems somewhat similar to the Knapsack problem[^], and Wikipedia (or Google) are a good place to start your search.
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It's similar to job scheduling, where the blocks are "jobs" (length of job = length of block) and the layers of the wall would represent the "machines" (number of layers = number of machines)
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Are there some good algorithms following this approach?
I have been working in this area and would love to learn more.
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IIRC Integer Linear Programming can solve it optimally, but everyone seems to use heuristic algorithms because solving an ILP problem is too slow for them. But ILP is not an algorithm but a way of specifying a problem. You can solve it with Branch and Bound (I may give it a try and see how slow it would really be).
It's quite annoying to search for good information about job scheduling with full in-advance knowledge - most papers about job scheduling deal with the online version and/or throw in some extra unknowns and restrictions.
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