[algogeeks] Re: text analysis

2006-10-25 Thread Ioannis Atsonios
Very quickly i believe that the problem you confront is more perceptual and at least as far as i can see you need a very good and robust feature extraction in order to be capable to compute the similarity (or distance in terms of machine learning/pattern classification)between the texts, which

[algogeeks] Re: Finding median in theta(n^lg3) time

2006-10-13 Thread Ioannis Atsonios
In order to find the median of an unsorted you can do it in O(n) time complexity.You can do it as J.Guo said,but you need from the quicksort the select subroutine.Try googling some keywords: select,quicksort,median-select,k-th element. Tarjan,etc proved that median can be done in O(n)(also i

[algogeeks] Re: Who want to participate in this task.

2006-09-12 Thread Ioannis Atsonios
I am also interested,please notify me . --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to algogeeks@googlegroups.com To unsubscribe from this group, send

[algogeeks] Re: Maximum spanning forest

2006-08-03 Thread Ioannis Atsonios
Yes you are right ,sorry..I thought something completely different..(unfortunately..:( ) --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Algorithm Geeks group. To post to this group, send email to

[algogeeks] Re: finding sub prime numbers

2006-07-14 Thread Ioannis Atsonios
why don't you try a brute force technique through a simple program,to see what it's gonna happen.You have a 4 nested loop(O(n^4)) e.g number x=abcd for(a=1t o 9) do {for(b=1 to 9)do {for(c=1 to 9)do {for (d=1 to 9)do { y=1000*a+100*b+10*c+d; if prime(y) and

[algogeeks] Re: Travelling Salesman Relaxation

2006-07-13 Thread Ioannis Atsonios
one type of relaxation is based on triangle inequality.e.g w(x1,x2)+w(x2,x3)w(x1,x3),where x1,x2,x3 are nodes(often called as euclidean tsp),Christofides gave an algorithm with approximation ratio 1.5. Also there are a lot of variants,you must have in mind that tsp is np-complete ,even if the

[algogeeks] Re: How to partition a set into two?

2006-07-10 Thread Ioannis Atsonios
It is true that the problem is NP-complete,albeit as DHyanesh said you can solve it via dynamic programming,the complexity of the algorithm is O(nW)(it is pseudopolynomial,because the W is proportional to the input represantation,which is unfortunately exponential). But you can find an

[algogeeks] Re: Capacitated Vehicle Routing Problem - Algorithm and Relaxation

2006-07-10 Thread Ioannis Atsonios
dear friend,i believe that a branch and bound technique would not be ideal(even simple to implement),I believe that you can you use an A* algorith,and try to think a good (and robust) heuristic function,albeit the inherent combinatorial explotion can be attacked quite efficiently(it is highly