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• Sorting tree with a materialized path?

  - by Ovid

  I have a tree structure in a table and it uses materialized paths to allow me to find children quickly. However, I also need to sort the results depth-first, as one would expect with threaded forum replies. id | parent_id | matpath | created ----+-----------+---------+---------------------------- 2 | 1 | 1 | 2010-05-08 15:18:37.987544 3 | 1 | 1 | 2010-05-08 17:38:14.125377 4 | 1 | 1 | 2010-05-08 17:38:57.26743 5 | 1 | 1 | 2010-05-08 17:43:28.211708 7 | 1 | 1 | 2010-05-08 18:18:11.849735 6 | 2 | 1.2 | 2010-05-08 17:50:43.288759 9 | 5 | 1.5 | 2010-05-09 14:02:43.818646 8 | 6 | 1.2.6 | 2010-05-09 14:01:17.632695 So the final results should actually be sorted like this: id | parent_id | matpath | created ----+-----------+---------+---------------------------- 2 | 1 | 1 | 2010-05-08 15:18:37.987544 6 | 2 | 1.2 | 2010-05-08 17:50:43.288759 8 | 6 | 1.2.6 | 2010-05-09 14:01:17.632695 3 | 1 | 1 | 2010-05-08 17:38:14.125377 4 | 1 | 1 | 2010-05-08 17:38:57.26743 5 | 1 | 1 | 2010-05-08 17:43:28.211708 9 | 5 | 1.5 | 2010-05-09 14:02:43.818646 7 | 1 | 1 | 2010-05-08 18:18:11.849735 How would I work that out? Can I do that in straight SQL (this is PostgreSQL 8.4) or should additional information be added to this table?

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• Adjacency List Tree Using Recursive WITH (Postgres 8.4) instead of Nested Set

  - by Koobz

  I'm looking for a Django tree library and doing my best to avoid Nested Sets (they're a nightmare to maintain). The cons of the adjacency list model have always been an inability to fetch descendants without resorting to multiple queries. The WITH clause in Postgres seems like a solid solution to this problem. Has anyone seen any performance reports regarding WITH vs. Nested Set? I assume the Nested set will still be faster but as long as they're in the same complexity class, I could swallow a 2x performance discrepancy. Django-Treebeard interests me. Does anyone know if they've implemented the WITH clause when running under Postgres? Has anyone here made the switch away from Nested Sets in light of the WITH clause?

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• easiest way to convert virtualbox snapshots to tree view

  - by amir beygi

  HI all My virtual box snapshot view is like this Name: Snapshot 2 (UUID: cb45aef4-54d4-4c4e-ad3e-dd7cccb6103a) Name: s131 (UUID: 8ec30c82-7796-4e51-8161-979f1b95fb0f) Name: s131 (UUID: 42066f33-969b-41f3-a779-7f6e2c45ea2c) Name: s131 (UUID: d71b9bc5-b862-46b5-ae4d-f88d3dd9756d) Name: s131 (UUID: 681896a9-7e61-4b5a-90bc-cb1bd785c6fc) Name: s131 (UUID: d7bf8593-d218-442d-b23b-4ee16e74087d) Name: s131 (UUID: e8b16fd2-7add-4294-b908-34c4e6dc79dc) Name: s131 (UUID: 57c3f5d7-d4ed-4a62-a7b8-5594f819e08e) Name: Snapshot 3 (UUID: 4a684149-9dd6-4bb2-baf5-5f590e91a344) Name: Snapshot 4 (UUID: d4cbaa7c-ae78-41e0-9962-46c587a9c667) Name: Snapshot 5 (UUID: 81567b6e-eea9-49a6-b3b8-a07f0be337d8) * and i want to convert this text to a tree like this Name: Snapshot 2 (UUID: cb45aef4-54d4-4c4e-ad3e-dd7cccb6103a) +--Name: s131 (UUID: 8ec30c82-7796-4e51-8161-979f1b95fb0f) +--Name: s131 (UUID: 42066f33-969b-41f3-a779-7f6e2c45ea2c) +--Name: s131 (UUID: d71b9bc5-b862-46b5-ae4d-f88d3dd9756d) +--Name: s131 (UUID: 681896a9-7e61-4b5a-90bc-cb1bd785c6fc) | +--Name: s131 (UUID: d7bf8593-d218-442d-b23b-4ee16e74087d) | +--Name: s131 (UUID: e8b16fd2-7add-4294-b908-34c4e6dc79dc) | +--Name: s131 (UUID: 57c3f5d7-d4ed-4a62-a7b8-5594f819e08e) +--Name: Snapshot 3 (UUID: 4a684149-9dd6-4bb2-baf5-5f590e91a344) +--Name: Snapshot 4 (UUID: d4cbaa7c-ae78-41e0-9962-46c587a9c667) +--Name: Snapshot 5 (UUID: 81567b6e-eea9-49a6-b3b8-a07f0be337d8) * or even an array that contents line number and parent's line number. My environment is linux, programming language is C, and i got this results from this shell command VBoxManage snapshot s2000 showvminfo s|grep Name|grep UUID

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• Experience/Articles about "decision tree" documentation?

  - by Philipp Keller

  I'm running an "defect fixing" group (developers do 2 weeks operations, then rotate). I want to build up a documentation "how to deal with problem x" - basically a decision tree: Is the problem in part x of the web site? Yes: Is the problem occurring in all browsers? Yes: ... No: ... No: ... The documentation should be written and extended by the people using it. Do you know of any book/article describing how that is best done, or is there a software (Mac OS X) that helps doing that?

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• SQL Loop over a family tree

  - by simon831

  Using SQL server 2008. I have a family tree of animals stored in a table, and want to give some information on how 'genetically diverse' (or not) the offspring is. In SQL how can I produce sensible metrics to show how closely related the parents are? Perhaps some sort of percentage of shared blood, or a number of generations to go back before there is a shared ancestor? AnimalTable Id Name mumId dadId select * from AnimalTable child inner join AnimalTable mum on child.[mumId] = mum.[Id] inner join AnimalTable dad on child.[dadId] = dad.[Id] inner join AnimalTable mums_mum on mum.[mumId] = mums_mum.[Id] inner join AnimalTable mums_dad on mum.[dadId] = mums_dad.[Id] inner join AnimalTable dads_mum on dad.[mumId] = dads_mum.[Id] inner join AnimalTable dads_dad on dad.[dadId] = dads_dad.[Id]

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• Subversion merging, tree merge

  - by krystan honour

  I need to merge changes from a branch back into trunk but want to continue work on the existing branch. I was going to use a re-integrate merge but realised this is not suitable as I will need to recreate my branch etc which for a variety of reasons is not desirable. What I really want to do is merge the current revisions in the branch down to head and then keep people working on their current working copies. So my question is , can tree merge be used to solve this or do I have to reintegrate and recreate.

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• Algorithm to aggregate values from child tree nodes

  - by user222164

  I have objects in a tree structure, I would like to aggregate status information from children nodes and update parent node with aggregated status. Lets say node A has children B1, B2, and B1 has C1, C2, C3 as children. Each of the nodes have a status attribute. Now if C1, C2, C3 are all complete then I would like to mark B1 as completed. And if C4, C5,C6,C7 are complete make B2 as complete. When B1 and B2 are both complete mark A as complete. I can go through these nodes in brute force method and make updates, could someone suggest an efficient algorithm to do it. A { B1 { C1, C2, C3}, B2 { C4, C5, C6, C7} }

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• Binary Search Tree node removal

  - by doc

  I've been trying to implement a delete function for a Binary Search Tree but haven't been able to get it to work in all cases. This is my latest attempt: if(t->get_left() == empty) *t = *t->get_left(); else if(t->get_right() == empty) *t = *t->get_right(); else if((t->get_left() != empty) && (t->get_right() != empty)) { Node* node = new Node(t->get_data(), t->get_parent(), t->get_colour(), t->get_left(), t->get_right()); *t = *node; } t is a node and empty is just a node with nothing in it. I'm just trying to swap the values but I'm getting a runtime error. Any ideas? Thanks

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• Algorithms to find longest common prefix in a sliding window.

  - by nn

  Hi, I have written a Lempel Ziv compressor and decompressor. I am seeking to improve the time to search the dictionary for a phrase. I have considered K-M-P and Boyer-Moore, but I think an algorithm that adapts to changes in the dictionary would be faster. I've been reading that binary search trees (AVL or with splays) improve the performance of compression time considerably. What I fail to understand is how to bootstrap the binary search tree and insert/remove data. I'm not actually quite sure the significance of each node in the binary search. I am searching for phrases so will each character be considered a node? Also how and what is inserted/removed from the search tree as new data enters the dictionary and old data is removed? The binary search tree sounds like a good payoff since it can adapt to the dictionary, but I'm just not quite sure of how it's used.

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• Finding height in Binary Search Tree

  - by mike

  Hey I was wondering if anybody could help me rework this method to find the height of a binary search tree. So far my code looks like this however the answer im getting is larger than the actual height by 1, but when I remove the +1 from my return statements its less than the actual height by 1? I'm still trying to wrap my head around recursion with these BST any help would be much appreciated. public int findHeight(){ if(this.isEmpty()){ return 0; } else{ TreeNode<T> node = root; return findHeight(node); } } private int findHeight(TreeNode<T> aNode){ int heightLeft = 0; int heightRight = 0; if(aNode.left!=null) heightLeft = findHeight(aNode.left); if(aNode.right!=null) heightRight = findHeight(aNode.right); if(heightLeft > heightRight){ return heightLeft+1; } else{ return heightRight+1; } }

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• nHibernate: Query tree nodes where self or ancestor matches condition

  - by Famous Nerd

  I have see a lot of competing theories about hierarchical queries in fluent-nHibernate or even basic nHibernate and how they're a difficult beast. Does anyone have any knowledge of good resources on the subject. I find myself needing to do queries similar to: (using a file system analog) select folderObjects from folders where folder.Permissions includes :myPermissionLevel or [any of my ancestors] includes :myPermissionLevel This is a one to many tree, no node has multiple parents. I'm not sure how to describe this in nHibernate specific terms or, even sql-terms. I've seen the phrase "nested sets" mentioned, is this applicable? I'm not sure. Can anyone offer any advice on approaches to writing this sort of nHibernate query?

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• Calculating depth and descendants of tree

  - by yuudachi

  Can you guys help me with the algorithm to do these things? I have preorder, inorder, and postorder implemented, and I am given the hint to traverse the tree with one of these orders. I am using dotty to label (or "visit") the nodes. Depth is the number of edges from the root to the bottom leaf, so everytime I move, I add +1 to the depth? Something like that? No idea about the algorithm for descendants. They are asking about the number of nodes a specific node has under itself. These are normal trees btw.

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• SimpleXML adding html into Hash tree

  - by Miriam Raphael Roberts

  Question: I have an xml file that I am pulling from the web and parsing. One of the items in the xml is a 'content' value that has HTML. I am using SimpleXML/XMLin to parse the file like so: $xml= eval { $data-XMLin($xmldata, forcearray = 1, suppressempty= +'') }; When I use Dumper to dump the hash, I dsicovered that SimpleXML is parsing the HTML into the hash tree. 'content' => { 'div' => [ { 'xmlns' => 'http://www.w3.org/1999/xhtml', 'p' => [ { 'a' => [ { 'href' => 'http://miamiherald.typepad.com/.a/6a00d83451b26169e20133ec6f4491970b-pi', 'style' => 'FLOAT: left', 'img' => [ etc..... This is not what I want. I want to just grab content inside of this entry. How do I do this?

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• GWT: Select a TreeItem with right click

  - by Ivan

  I'm capturing a right click event to show a context menu. What I haven't been able to figure out, is how to make the right click actually select the TreeItem, prior to showing of context menu. All help is appreciated. private Tree tree = new Tree() { @Override public void onBrowserEvent(Event event) { if (event.getTypeInt() == Event.ONCONTEXTMENU) { DOM.eventPreventDefault(event); showContextMenu(event); } super.onBrowserEvent(event); } @Override protected void setElement(Element elem) { super.setElement(elem); sinkEvents(Event.ONCONTEXTMENU); } };

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• A RecursiveParentChildIterator -- like the RecursiveDirectoryIterator

  - by Stephen J. Fuhry

  There are tons of examples of using the RecursiveIterator to flatten a tree structure.. but what about using it to explode a tree structure? Is there an elegant way to use this, or some other SPL library to recursively build a tree (read: turn a flat array into array of arbitrary depth) given a table like this: SELECT id, parent_id, name FROM my_tree EDIT: You know how you can do this with Directories? $it = new RecursiveDirectoryIterator("/var/www/images"); foreach(new RecursiveIteratorIterator($it) as $file) { echo $file . PHP_EOL; } .. What if you could do something like this: $it = new RecursiveParentChildIterator($result_array); foreach(new RecursiveIteratorIterator($it) as $group) { echo $group->name . PHP_EOL; // this would contain all of the children of this group, recursively $children = $group->getChildren(); } :END EDIT

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• Long IF tree with strings

  - by DalGr

  I have a C program which uses Lua for scripting. In order to keep readability and avoid importing several constants within the individual Lua states, I condense a large amount of functions within a simple call (such as "ObjectSet(id, "ANGLE", 45)"), by using an "action" string. To do this I have a large if tree comparing the action string to a list (such as "if(stringcompare(action, "ANGLE") ... else if (stringcompare(action, "X")... etc") This approach works well, and within the program it's not really slow, and is fairly quick to add a new action. But I kind of feel perfectionist. Is there a better way to do this in C? And having Lua in heavy use, maybe there is a way to use it for this purpose? (embedded "chunks" making a dictionary?) Although this part is mostly curiosity.

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• Has anybody used the WB B-tree library?

  - by Chris B

  I stumbled across the WB on-disk B-tree library: http://people.csail.mit.edu/jaffer/WB It seems like it could be useful for my purposes (swapping data to disk during very large statistical calculations that do not fit in memory), but I was wondering how stable it is. Reading the manual, it seems worringly 'researchy' - there are sections labelled [NOT IMPLEMENTED] etc. But maybe the manual is just out-of-date. So, is this library useable? Am I better off looking at Tokyo Cabinet, MemcacheDB, etc.? By the way I am working in Java.

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• How to find longest common substring using trees?

  - by user384706

  The longest common substring problem according to wiki can be solved using a suffix tree. From wiki: The longest common substrings of a set of strings can be found by building a generalised suffix tree for the strings, and then finding the deepest internal nodes which have leaf nodes from all the strings in the subtree below it I don't get this. Example: if I have: ABCDE and XABCZ then the suffix tree is (some branches from XABCZ omitted due to space): The longest common substring is ABC but it is not I can not see how the description of wiki helps here. ABC is not the deepest internal nodes with leaf nodes. Any help to understand how this works?

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• how can I declare a value deep in an object tree using variable properties in javascript

  - by joshs

  I am trying to have a javascript object tree behave like a php associative array in the following way. var key1 = 'a'; var key2 = 'b'; var key3 = 'c'; var obj[key1][key2][key3] = 'd'; However, in javascript I believe you need to define each property/object pair individually, forming deeper leaves. Something like: var obj[key1] = {}; var obj[key1][key2] = {}; ... Is there a way to simplify or shorten this script? Thanks

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• improving drawing pythagoras tree

  - by sasquatch90

  Hello. I have written program for drawing pythagoras tree fractal. Can anybody see any way of improving it ? Now it is 120 LOc. I was hoping to shorten it to ~100... import javax.swing.*; import java.util.Scanner; import java.awt.Color; import java.awt.Dimension; import java.awt.Graphics; import javax.swing.JComponent; public class Main extends JFrame {; public Main(int n) { setSize(900, 900); setTitle("Pythagoras tree"); Draw d = new Draw(n); add(d); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setVisible(true); } private int pow(int n){ int pow = 2; for(int i = 1; i < n; i++){ if(n==0){ pow = 1; } pow = pow*2; } return pow; } public static void main(String[] args) { Scanner sc = new Scanner(System.in); System.out.print("Give amount of steps: "); int steps = sc.nextInt(); new Main(steps); } } class Draw extends JComponent { private int height; private int width; private int steps; public Draw(int n) { height = 800; width = 800; steps = n; Dimension d = new Dimension(width, height); setMinimumSize(d); setPreferredSize(new Dimension(d)); setMaximumSize(d); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); g.setColor(Color.white); g.fillRect(0, 0, width, height); g.setColor(Color.black); int w = width; int h = height; int x1, x2, x3, x4, x5, y1, y2, y3, y4, y5; int base = w/7; x1 = (w/2)-(base/2); x2 = x1; x3 = (w/2)+(base/2); x4 = x3; x5 = w/2; y1 = (h-(h/15))-base; y2 = h-(h/15); y3 = y2; y4 = y1; y5 = (h-(h/15))-(base+(base/2)); //paint g.drawLine(x1, y1, x2, y2); g.drawLine(x2, y2, x3, y3); g.drawLine(x3, y3, x4, y4); g.drawLine(x1, y1, x4, y4); int n1 = steps; n1--; if(n1>0){ g.drawLine(x1, y1, x5, y5); g.drawLine(x4, y4, x5, y5); paintMore(n1, g, x1, x5, x4, y1, y5, y4); paintMore(n1, g, x4, x5, x1, y4, y5, y1); } } public void paintMore(int n1, Graphics g, double x1_1, double x2_1, double x3_1, double y1_1, double y2_1, double y3_1){ double x1, x2, x3, x4, x5, y1, y2, y3, y4, y5; //counting x1 = x1_1 + (x2_1-x3_1); x2 = x1_1; x3 = x2_1; x4 = x2_1 + (x2_1-x3_1); x5 = ((x2_1 + (x2_1-x3_1)) + ((x2_1-x3_1)/2)) + ((x1_1-x2_1)/2); y1 = y1_1 + (y2_1-y3_1); y2 = y1_1; y3 = y2_1; y4 = y2_1 + (y2_1-y3_1); y5 = ((y1_1 + (y2_1-y3_1)) + ((y2_1-y1_1)/2)) + ((y2_1-y3_1)/2); //paint g.setColor(Color.green); g.drawLine((int)x1, (int)y1, (int)x2, (int)y2); g.drawLine((int)x3, (int)y3, (int)x4, (int)y4); g.drawLine((int)x1, (int)y1, (int)x4, (int)y4); n1--; if(n1>0){ g.drawLine((int)x1, (int)y1, (int)x5, (int)y5); g.drawLine((int)x4, (int)y4, (int)x5, (int)y5); paintMore(n1, g, x1, x5, x4, y1, y5, y4); paintMore(n1, g, x4, x5, x1, y4, y5, y1); } } }

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• Stealing the contents of another application's tree view

  - by User1

  I have an application with a very large TreeView control in Java. I want to get the contents of the tree control in a list (just strings not a JList) of XPath-like elements of leaves only. Here's an example root |-Item1 |-Item1.1 |-Item1.1.1 (leaf) |-Item1.2 (leaf) |-Item2 |-Item2.1 (leaf) Would output: /Item1/Item1.1/Item1.1.1 /Item1/Item1.2 /Item2/Item2.1 I don't have any source code or anything handy like that. Is there I tool I can use to dig into the Window item itself and pull out this data? I don't mind if there are a few post-processing steps because typing it in by hand is my only other option.

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• Picking apples off a tree

  - by John Retallack

  I have the following problem: I am given a tree with N apples, for each apple I am given it's weight and height. I can pick apples up to a given height H, each time I pick an apple the height of every apple is increased with U. I have to find out the maximum weight of apples I can pick. 1 = N = 100000 0 < {H, U, apples' weight and height, maximum weight} < 231 Example: N=4 H=100 U=10 height weight 82 30 91 10 93 5 94 15 The answer is 45: first pick the apple with the weight of 15 then the one with the weight of 30. Could someone help me approach this problem?

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• How to implement B+ Tree for file systems ?

  - by user312544

  I have a text file which contains some info on extents about all the files in the file system, like below C:\Program Files\abcd.txt 12345 100 23456 200 C:\Program Files\bcde.txt 56789 50 26746 300 ... Now i have another binary which tries to find out about extents for all the files. Now currently i am using linear search to find extent info for the files in the above mentioned text file. This is a time consuming process. Is there a better way of coding this ? Like Implementing any good data structure like BTree. If B+ Tree is used what is the key, branch factor i need to use ?

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• Deep copying of tree view nodes.

  - by Kanags.Net

  I'm trying to copy a treeview nodes to treenodecollection for some other processing. When i execute the treeview.nodes.clear() in the next line, my treenodecollection is becoming null. Can you please tell me how to copy the treeview nodes to treenodecollection and keep the copies of the nodes even after calling Clear method of actual tree view nodes? TreeNodeCollection tnc = null; private TypeIn() { tnc = treeView1.Nodes; treeView1.Nodes.Clear(); //Now my tnc becomes null, but I want the tnc for future use. }

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• How to manage different form contexts of same form element in single DOM tree

  - by nimp

  Hi, As my question title could be bit unclear to you (I tried best), following is what I'm exactly trying to do. I'm having a form element (say a user_info form), where such form elements will be generated for different users by java script and displayed in different js tabs (example: dojo tabs). once form elements are generated, later I need to react on user actions performed on different html elements defined inside user_info form. In this case I need to identify what is the context (in which user_info form element) in which user is working on. The simplest example would be how to retrieve form id of the form in which user actions are being performed. According to my understanding, I can not simply retrieve from by form id, because now DOM tree contains duplicate form instances of the same from element. So, IS there anyway, I could identify form context based on the user actions on its input elements. Thank You.

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