algorithm

Need help iteratating over an array, retrieve two possibilites, no repeats, for Poker AI

I can't really think of a good way to word this question, nor a good title, and maybe the answer is so ridiculously simple that I am missing it. I am working on a poker AI, and I want to calculate the number of hands that exist which are better than mine. I understand how to that, but what I can't figure out is the best way to iterate ...

Best way to get the highest sum from a Matrix (using Java but algorithm is the issue here)

Sorry I dont know the correct terminology to use but I have a 3x3 matrix like this 1 3 4 5 4 5 2 2 5 and I want get the highest score by picking a value from each row/column but I cant pick the same row or column more than once , so the answer in this case is 3 + 5 + 5 = 13 (row0,col1 + row1,col0 + row2,col2) 4 + 5 + 5 = 14 is ...

HPC (mainly on Java)

I'm looking for some way of using the number-crunching ability of a GPU (with Java perhaps?) in addition to using the multiple cores that the target machine has. I will be working on implementing (at present) the A* Algorithm but in the future I hope to replace it with a Genetic Algorithm of sorts. I've looked at Project Fortress but as ...

Books on string algorithms

There have been numerous posts on string algorithms: http://stackoverflow.com/questions/246961/algorithm-to-find-similar-text, http://stackoverflow.com/questions/451884/similar-string-algorithm, http://stackoverflow.com/questions/613133/efficient-string-matching-algorithm However, no general literature was mentioned. Could anyone ...

Can Goldberg algorithm in ocamlgraph be used to find Minimum Cost Flow graph?

I'm looking for an implementation to the Minimum Cost Flow graph problem in OCaml. OCaml library ocamlgraph has Goldberg algorithm implementation. The paper called Efficient implementation of the Goldberg-Tarjan minimum-cost flow algorithm is noting that Goldberg-Tarjan algorithm can find minimum cost graph. Question is, does ocamlgrap...

How can I transform latitude and longitude to x,y in Java?

Hello, I am working on a geographic project in Java. The input are coordinates : 24.4444 N etc Output: a PLAIN map (not round) showing the point of the coordinates. I don't know the algorithm to transform from coordinates to x,y on a JComponent, can somebody help me? The map looks like this: http://upload.wikimedia.org/wikipedia/c...

What is the best way to combine GoogleBase results with other results

Hi everyone, I am recently working on a real estate website http://www.rbasket.com.au and one of the requirement is to merge result from GoogleBase housing with the results from our existing internal search engine. According to Google TOS, all traffic from GoogleBase must be realtime (caching is not allowed). So my interpretation is th...

Efficient data structure for word lookup with wildcards

Hi there, I need to match a series of user inputed words against a large dictionary of words (to ensure the entered value exists). So if the user entered: "orange" it should match an entry "orange' in the dictionary. Now the catch is that the user can also enter a wildcard or series of wildcard characters like say "or__ge" which wo...

What is a good measure of strength of a link and influence of a node?

In the context of social networks, what is a good measure of strength of a link between two nodes? I am currently thinking that the following should give me what I want: For two nodes A and B: Strength(A,B) = (neighbors(A) intersection neighbors(B))/neighbors(A) where neighbors(X) gives the total number of nodes directly connected to X...

Is there a website to look up common, already written functions?

I'm sitting here writing a function that I'm positive has been written before, somewhere on earth. It's just too common to have not been attempted, and I'm wondering why I can't just go to a website and search for a function that I can then copy and paste into my project in 2 seconds, instead of wasting my day reinventing the wheel. Su...

Linear-time algorithms for sorting vertices in polygon contours

I figured out an algorithm that lets me turn my holed polygons into trapezoids in linear time if I have vertex indices sorted from lowest coordinate to highest. I get simple polygons as contours. They have certain order that might be exploited most of the time. So giving these conditions, is there a near-linear-time algorithm on sortin...

Diagonal of polygon is inside or outside?

I have three consecutive points of polygon, say p1,p2,p3. Now I wanted to know whether the orthogonal between p1 and p3 is inside the polygon or outside the polygon. I am doing it by taking three vectors v1,v2 and v3. And the point before the point p1 in polygon say p0. v1 = (p0 - p1) v2 = (p2 - p1) v3 = (p3 - p1) With reference t...

Merge overlapping triangles into a polygon

I've got a bunch of overlapping triangles from a 3D model projected into a 2D plane. I need to merge each island of touching triangles into a closed, non-convex polygon. The resultant polygons shouldn't have any holes in them (since the source data doesn't). Many of the source triangles share (floating point identical) edges with other...

Where can I find the diff algorithm?

Where can I find an explanation and implementation of the diff algorithm? First of all I have to recognize that I'm not sure if this is the correct name of the algorithm. For example, how does Stack Overflow mark the differences between two edits of the same question? PS: I know the C and PHP programming languages. ...

How to calculate the current index?

Hi, I have written an algorithm which iteratively solves the problem. The first iteration consists of 6 steps and all the following iterations consist of 5 steps (first step is skipped). What I want to calculate is the current (local) step in the iteration from current global step. For example if there are 41 steps in total which mean...

Minimum and maximum height of binary search trees, 2-3-4 trees and B trees.

Hi, Can anyone please tell me how you find the min/max height of B trees, 2-3-4 trees and binary search trees? Thanks. PS: This is not homework. ...

Return the difference between the lowest and highest key - Binary Search Tree

This is a past exam paper on binary search trees I am attempting. I have no way to check if the output is correct as I am not capable of building one of these things. The question is in the title class Tree{ Tree left; Tree right; int key; public static int span(Tree tree) { if ( tree == null ){ ...

How do I convert decimal numbers to binary in Perl?

I am trying to make a program that converts decimal numbers or text into binary numbers in perl. The program asks for user input of a character or string , and then prints out the result to the console. How do I do this? My code I have been working on is below, but i cannot seem to fix it. print "Enter a number to convert: "; chomp($dec...

How do you tell if two wildcards overlap?

Given two strings with * wildcards, I would like to know if a string could be created that would match both. For example, these two are a simple case of overlap: Hello*World Hel* But so are all of these: *.csv reports*.csv reportsdump.csv Is there an algorithm published for doing this? Or perhaps a utility function in Windows or...

Point covering problem

I recently had this problem on a test: given a set of points m (all on the x-axis) and a set n of lines with endpoints [l, r] (again on the x-axis), find the minimum subset of n such that all points are covered by a line. Prove that your solution always finds the minimum subset. The algorithm I wrote for it was something to the effect ...