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  • F#: Recursive collect and filter over N-ary Tree

    - by RodYan
    This is hurting my brain! I want to recurse over a tree structure and collect all instances that match some filter into one list. Here's a sample tree structure type Tree = | Node of int * Tree list Here's a test sample tree: let test = Node((1, [Node(2, [Node(3,[]); Node(3,[])]); Node(3,[])])) Collecting and filtering over nodes with and int value of 3 should give you output like this: [Node(3,[]);Node(3,[]);Node(3,[])]

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  • In-order tree traversal

    - by Chris S
    I have the following text from an academic course I took a while ago about in-order traversal (they also call it pancaking) of a binary tree (not BST): In-order tree traversal Draw a line around the outside of the tree. Start to the left of the root, and go around the outside of the tree, to end up to the right of the root. Stay as close to the tree as possible, but do not cross the tree. (Think of the tree — its branches and nodes — as a solid barrier.) The order of the nodes is the order in which this line passes underneath them. If you are unsure as to when you go “underneath” a node, remember that a node “to the left” always comes first. Here's the example used (slightly different tree from below) However when I do a search on google, I get a conflicting definition. For example the wikipedia example: Inorder traversal sequence: A, B, C, D, E, F, G, H, I (leftchild,rootnode,right node) But according to (my understanding of) definition #1, this should be A, B, D, C, E, F, G, I, H Can anyone clarify which definition is correct? They might be both describing different traversal methods, but happen to be using the same name. I'm having trouble believing the peer-reviewed academic text is wrong, but can't be certain.

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  • Syntax highlight in java for android

    - by Mohit Deshpande
    I want to build an notepad-style application on android that will have syntax highlighting. But when I search around the web, I find the syntax highlighting can be done only through use of an awt class. How could I syntax highlight in maybe a custom EditText or TextView view? I know that the release of a syntax highlighter is sort of anticipated, so I want to add my syntax highlighter on the market.

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  • MySQL Syntax error when trying to reset Joomla password

    - by Arthur
    I'm trying to reset my Joomla admin password by executing the following code in MySQL: INSERT INTO `jos_users` (`id`,`name`, `username`, `password`, `params`) VALUES (LAST_INSERT_ID(),'Administrator2', 'admin2', 'd2064d358136996bd22421584a7cb33e:trd7TvKHx6dMeoMmBVxYmg0vuXEA4199', ''); INSERT INTO `jos_user_usergroup_map` (`user_id`,`group_id`) VALUES (LAST_INSERT_ID(),'8'); When I attempt to execute it, I get the following error: Failed to execute SQL : SQL INSERT INTO `jos_users` (`id`,`name`, `username`, `password`, `params`) VALUES (LAST_INSERT_ID(),'Administrator2', 'admin2', 'd2064d358136996bd22421584a7cb33e:trd7TvKHx6dMeoMmBVxYmg0vuXEA4199', ''); INSERT INTO `jos_user_usergroup_map` (`user_id`,`group_id`) VALUES (LAST_INSERT_ID(),'8'); failed : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'INSERT INTO `jos_user_usergroup_map` (`user_id`,`group_id`) VALUES (LAST_INSERT_' at line 1 Could someone tell me where my Syntax might be wrong? I'm using MySQL version 5.0.95.

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  • Scene graphs and spatial partitioning structures: What do you really need?

    - by tapirath
    I've been fiddling with 2D games for awhile and I'm trying to go into 3D game development. I thought I should get my basics right first. From what I read scene graphs hold your game objects/entities and their relation to each other like 'a tire' would be the child of 'a vehicle'. It's mainly used for frustum/occlusion culling and minimizing the collision checks between the objects. Spatial partitioning structures on the other hand are used to divide a big game object (like the map) to smaller parts so that you can gain performance by only drawing the relevant polygons and again minimizing the collision checks to those polygons only. Also a spatial partitioning data structure can be used as a node in a scene graph. But... I've been reading about both subjects and I've seen a lot of "scene graphs are useless" and "BSP performance gain is irrelevant with modern hardware" kind of articles. Also some of the game engines I've checked like gameplay3d and jmonkeyengine are only using a scene graph (That also may be because they don't want to limit the developers). Whereas games like Quake and Half-Life only use spatial partitioning. I'm aware that the usage of these structures very much depend on the type of the game you're developing so for the sake of clarity let's assume the game is a FPS like Counter-Strike with some better outdoor environment capabilities (like a terrain). The obvious question is which one is needed and why (considering the modern hardware capabilities). Thank you.

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  • On Windows 7, dir or tree can't show unicode characters, even starting cmd with cmd /U

    - by Jian Lin
    On Windows 7, dir or tree can't show unicode characters, even starting cmd with cmd /U So I would press Window Key + R to run something, and type in cmd /U so that the content might handle Unicode. And then using dir or tree /F, the content in Unicode won't show as Unicode. (in Window Explorer (file manager), the Unicode will show) Is there a way to handle it? To get Unicode characters to test your filenames, you can go to http://news.google.com/news?edchanged=1&ned=tw and you will be able to get many Unicode characters there (UTF-8)

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  • How to Serialize Binary Tree

    - by Veljko Skarich
    I went to an interview today where I was asked to serialize a binary tree. I implemented an array-based approach where the children of node i (numbering in level-order traversal) were at the 2*i index for the left child and 2*i + 1 for the right child. The interviewer seemed more or less pleased, but I'm wondering what serialize means exactly? Does it specifically pertain to flattening the tree for writing to disk, or would serializing a tree also include just turning the tree into a linked list, say. Also, how would we go about flattening the tree into a (doubly) linked list, and then reconstructing it? Can you recreate the exact structure of the tree from the linked list? Thank you/

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  • recursion tree and binary tree cost calculation

    - by Tony
    Hi all, I've got the following recursion: T(n) = T(n/3) + T(2n/3) + O(n) The height of the tree would be log3/2 of 2. Now the recursion tree for this recurrence is not a complete binary tree. It has missing nodes lower down. This makes sense to me, however I don't understand how the following small omega notation relates to the cost of all leaves in the tree. "... the total cost of all leaves would then be Theta (n^log3/2 of 2) which, since log3/2 of 2 is a constant strictly greater then 1, is small omega(n lg n)." Can someone please help me understand how the Theta(n^log3/2 of 2) becomes small omega(n lg n)?

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  • SQL server - climb up in the tree structure

    - by Vytas999
    Hello. I have some sql table, named Object, which saves tree data in fields ObjectID, ParentID, and others. I have implemented recurse procedure, which select everything down by objectID from tree, like this: 1. 1.1. 1.2. 1.2.1. ... Now o need to "Climb up" - by some ObjectID i need to select everything Up, like this: 1.2.1. 1.2. 1. How i can do that? In example, my "down" procedure looks like: ALTER PROCEDURE [dbo].[Object_SelectDownByRoot_Simple] @ObjectID int AS WITH tree (ObjectID, ParentID, ObjectName, ObjectCode) AS ( SELECT ObjectID, ParentID, ObjectName, ObjectCode FROM dbo.[ObjectQ] ofs WHERE( ObjectID = @ObjectID ) UNION ALL SELECT ofs.ObjectID, ofs.ParentID, ofs.ObjectName, ofs.ObjectCode FROM dbo.[ObjectQ] ofs JOIN tree ON tree.ObjectID = ofs.ParentID ) SELECT ObjectID, ParentID, ObjectName, ObjectCode FROM tree

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  • how do i supply data to my gwt tree

    - by molleman
    Hello, So i need to create a tree with tree items for my gwt project. i am using the composite pattern to store all the information i need to be placed within a tree. A User has a root Folder that extends Hierarchy, this root Folder then has a list of Hierarchy objects, that can be FileLocations or Folders. Trouble i am having is building my tree based on this pattern. this data is all stored using hibernate in a mysql database How would i be able to implement this as a tree in gwt. Also the tree item that i create would have to reference back to the object so i can rename or move it.

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  • On Windows 7, dir or tree can't show unicode characters, even starting cmd with cmd /U

    - by ????
    On Windows 7, dir or tree can't show unicode characters, even starting cmd with cmd /U So I would press Window Key + R to run something, and type in cmd /U so that the content might handle Unicode. And then using dir or tree /F, the content in Unicode won't show as Unicode. (in Window Explorer (file manager), the Unicode will show) Is there a way to handle it? To get Unicode characters to test your filenames, you can go to http://news.google.com/news?edchanged=1&ned=tw and you will be able to get many Unicode characters there (UTF-8)

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  • Pure functional bottom up tree algorithm

    - by Axel Gneiting
    Say I wanted to write an algorithm working on an immutable tree data structure that has a list of leaves as its input. It needs to return a new tree with changes made to the old tree going upwards from those leaves. My problem is that there seems to be no way to do this purely functional without reconstructing the entire tree checking at leaves if they are in the list, because you always need to return a complete new tree as the result of an operation and you can't mutate the existing tree. Is this a basic problem in functional programming that only can be avoided by using a better suited algorithm or am I missing something?

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  • Correcting tree from messed up file tree in NTFS partition

    - by Fullmooninu
    It's a real messed situation, but I'm quite at the end of my options. It's my personal hardrive, so it's very important for me, and yes, I have no backup =( The short story: 1) I have two discs. One with Windows, and another where I had a bit of empty space at the front of the disk, so i could install Linux. The rest was occupied by a 1.8TB NTFS partition filled with data. 2) I installed Linux, and after a while realized there was not enough space for everything, so I tried using Gparted, and told it to re-size the NTFS partition, to a lesser size. 3) The system jammed. I had to reboot and broke the Resizing operation. Here's what I did to fix it: a) Rebooted into Linux Live, and used Testdisk,to deep analyze the disk, and recover the possible partitions. It found several versions of the NTFS partitions, probably made during the resizing. I told Testdisk to open every one of them, and only one could list its files. When trying to open the other options on Testdisk, it showed an error message. I assumed the one without errors, to be the correct one, and I told Testdisk to recover the partition, and write a new MBR. b) The partition had errors, and Linux has a NTFS fixing tool, used it, but the system still had errors. c) So I booted into windows and use chkdsk to correct all errors in the partition. d) Everything seems fine, but now, back in Windows, when I open one file, it opens another file, or part of another file. As in, some files took up the position of other files. What I think happened is that I recovered an old tree, and not the most current one. And that one just happened to be intact, while the most recent one was damaged. As such, the files that were moved during the failed resizing, were now, during the automatic correction, assumed wrongly to be in their correct places. So when I open a file, it tries to open another one. Radiohead - Creep.mp3 will open and it will actually be a bit from another song, or even code from a jpg. Some files seem to be all right, but others have seemed to have had their position taken by others. Anyone knows of something really powerful that can help me solve this?

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  • Array "tree" creation from db table

    - by Tural Teyyuboglu
    Trying to create array tree for db driven navigation. Getting following errur: array_key_exists() expects exactly 2 parameters, 1 given on line if (!array_key_exists($tree[$parent]['children'][$id])) Function looks like that $tree = array(); $sql = "SELECT id, parent, name FROM menu WHERE parent ... etc.... "; $results = mysql_query($sql) or die(mysql_error()); while(list($id, $parent, $name) = mysql_fetch_assoc($results)) { $tree[$id] = array('name' => $name, 'children' => array(), 'parent' => $parent); if (!array_key_exists($tree[$parent]['children'][$id])) { $tree[$parent]['children'][$id] = $id; } } Db structure How can I fix that? Whats wrong in this function?

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  • Mac-native text editor that can syntax-highlight diff files?

    - by strawtarget
    I do something like "svn diff /mystuff/current.diff". I want to view this .diff file with syntax highlighting. jEdit does it, but it's a huge beast and it takes a while to start up. I want something lightweight/native. Smultron/Fraise, TextWrangler, TextEdit, Dashcode don't seem to highlight .diff files. FileMerge seems to want to generate diff files, not show you existing ones. TextMate does the trick, but it's not free. I'd feel happier dropping $50 US if I was going to take advantage of it for anything more than a diff viewer. Are there any alternatives to jEdit or TextMate that I should consider?

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  • Template syntax for users - is there a right way to do it?

    - by RickM
    Ok, I'm in the middle of building a saas system, and as part of that, the hosted clients need to be able to edit certain layout templates, baqsically just html, css and javascript files. I'm obviously going to be wanting to use a template syntax here as it would be dumb to let people execute PHP code, so in this instance template syntax does need to be used. I know that in the grand scale of things, this is a very minor thing, but what template syntax do you use, and why? Is there one that's considered better than others? I've seen all sorts being used with no real consistency, for example: Smarty Style: {$someVar} {foreach from="foo" item="bar"} {$bar.food} {/foreach} ASP Style: {% someVar %} {% foreach foo as bar %} {% bar.food %} {% endforeach %} HTML Style: <someVar> <foreach from="foo" item="bar"> <bar:food> </foreach> PyroCMS/FuelPHP "LEX" Style: {{ someVar }} {{ foreach from="foo" item="bar" }} {{ bar:food }} {{ endforeach }} Obviously these arent 100% accurate (for example, LEX is used alongside PHP for loops), and are only to give you an example of what I mean. What, in your opinion would be the best one (if any) to go with. I ask this bearing in mind that people using this are likely to be novice users. I did look around at a bunch of hosted CMS and E-Commerce systems as these seem to make use of user-editable templates, and most seem to be using some form of their own syntax. I should note that whatever style I end up going with, it will be with a custom template handler due to the complexity of the system and how template files are stored. Plus I'd not want to touch the likes of Smarty with a barge pole!

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  • Most efficient Implementation a Tree in C++

    - by Topo
    I need to write a tree where each element may have any number of child elements, and because of this each branch of the tree may have any length. The tree is only going to receive elements at first and then it is going to use exclusively for iterating though it's branches in no specific order. The tree will have several million elements and must be fast but also memory efficient. My plan makes a node class to store the elements and the pointers to its children. When the tree is fully constructed, it would be transformed it to an array or something faster and if possible, loaded to the processor's cache. Construction and the search on the tree are two different problems. Can I focus on how to solve each problem on the best way individually? The construction of has to be as fast as possible but it can use memory as it pleases. Then the transformation into a format that give us speed when iterating the tree's branches. This should preferably be an array to avoid going back and forth from RAM to cache in each element of the tree. So the real question is which is the structure to implement a tree to maximize insert speed, how can I transform it to a structure that gives me the best speed and memory?

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  • Counting leaf nodes in hierarchical tree

    - by timn
    This code fills a tree with values based their depths. But when traversing the tree, I cannot manage to determine the actual number of children. node-cnt is always 0. I've already tried node-parent-cnt but that gives me lots of warnings in Valgrind. Anyway, is the tree type I've chosen even appropriate for my purpose? #include <string.h> #include <stdio.h> #include <stdlib.h> #ifndef NULL #define NULL ((void *) 0) #endif // ---- typedef struct _Tree_Node { // data ptr void *p; // number of nodes int cnt; struct _Tree_Node *nodes; // parent nodes struct _Tree_Node *parent; } Tree_Node; typedef struct { Tree_Node root; } Tree; void Tree_Init(Tree *this) { this->root.p = NULL; this->root.cnt = 0; this->root.nodes = NULL; this->root.parent = NULL; } Tree_Node* Tree_AddNode(Tree_Node *node) { if (node->cnt == 0) { node->nodes = malloc(sizeof(Tree_Node)); } else { node->nodes = realloc( node->nodes, (node->cnt + 1) * sizeof(Tree_Node) ); } Tree_Node *res = &node->nodes[node->cnt]; res->p = NULL; res->cnt = 0; res->nodes = NULL; res->parent = node; node->cnt++; return res; } // ---- void handleNode(Tree_Node *node, int depth) { int j = depth; printf("\n"); while (j--) { printf(" "); } printf("depth=%d ", depth); if (node->p == NULL) { goto out; } printf("value=%s cnt=%d", node->p, node->cnt); out: for (int i = 0; i < node->cnt; i++) { handleNode(&node->nodes[i], depth + 1); } } Tree tree; int curdepth; Tree_Node *curnode; void add(int depth, char *s) { printf("%s: depth (%d) > curdepth (%d): %d\n", s, depth, curdepth, depth > curdepth); if (depth > curdepth) { curnode = Tree_AddNode(curnode); Tree_Node *node = Tree_AddNode(curnode); node->p = malloc(strlen(s)); memcpy(node->p, s, strlen(s)); curdepth++; } else { while (curdepth - depth > 0) { if (curnode->parent == NULL) { printf("Illegal nesting\n"); return; } curnode = curnode->parent; curdepth--; } Tree_Node *node = Tree_AddNode(curnode); node->p = malloc(strlen(s)); memcpy(node->p, s, strlen(s)); } } void main(void) { Tree_Init(&tree); curnode = &tree.root; curdepth = 0; add(0, "1"); add(1, "1.1"); add(2, "1.1.1"); add(3, "1.1.1.1"); add(4, "1.1.1.1.1"); add(2, "1.1.2"); add(0, "2"); handleNode(&tree.root, 0); }

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  • Updating a Minimum spanning tree when a new edge is inserted

    - by Lynette
    Hello, I've been presented the following problem in University: Let G = (V, E) be an (undirected) graph with costs ce = 0 on the edges e € E. Assume you are given a minimum-cost spanning tree T in G. Now assume that a new edge is added to G, connecting two nodes v, tv € V with cost c. a) Give an efficient algorithm to test if T remains the minimum-cost spanning tree with the new edge added to G (but not to the tree T). Make your algorithm run in time O(|E|). Can you do it in O(|V|) time? Please note any assumptions you make about what data structure is used to represent the tree T and the graph G. b)Suppose T is no longer the minimum-cost spanning tree. Give a linear-time algorithm (time O(|E|)) to update the tree T to the new minimum-cost spanning tree. This is the solution I found: Let e1=(a,b) the new edge added Find in T the shortest path from a to b (BFS) if e1 is the most expensive edge in the cycle then T remains the MST else T is not the MST It seems to work but i can easily make this run in O(|V|) time, while the problem asks O(|E|) time. Am i missing something? By the way we are authorized to ask for help from anyone so I'm not cheating :D Thanks in advance

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  • Display a tree dijit using zend framework

    - by churris43
    I am trying to display a tree of categories and subcategories by using dijits with zend framework. Haven't been able to find a good example. This is what I've got: Basically I got the following code as my action: class SubcategoriesController extends Zend_Controller_Action{ ..... public function loadtreeAction() { Zend_Dojo::enableView($this->view); Zend_Layout::getMvcInstance()->disableLayout(); //Creating a sample tree of categories and subcategories $a["cat1"]["id"] = "id1"; $a["cat1"]["name"] = "Category1"; $a["cat1"]["type"] = "category"; $subcat1 = array("id" => "Subcat1","name" => "Subcategory1" , "type" => "subcategory"); $subcat2 = array("id" => "Subcat12","name" => "Subcategory12" , "type" => "subcategory"); $a["cat1"]["children"] = array($subcat1,$subcat2); $treeObj = new Zend_Dojo_Data('id', $a); $treeObj->setLabel('name'); $this->view->tree = $treeObj->toJson(); } .... } And on my view: <?php $this->dojo()->requireModule('dojo.data.ItemFileReadStore'); $this->dojo()->requireModule('dijit.Tree'); $this->dojo()->requireModule('dojo.parser'); ?> <div dojoType="dojo.data.ItemFileReadStore" url="/Subcategories/loadtree" jsId="store"></div> <div dojoType="dijit.tree.ForestStoreModel" jsId="treeModel" store="store" rootId="root" rootLabel="List of Categories" childrenAttrs="children" query="{type:'category'}"></div> <div dojoType="dijit.Tree" model="treeModel" labelAttrs="ListOfCategories"></div> It doesn't even seem to try to load the tree at all. Any help is appreciated

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  • Is there a language offering LISP-like macros with a more complex syntax?

    - by blubb
    LISP's macros are extremely powerful constructs, and the inability to introspect and modify the program itself beyond the method signature level has always struck me as a limitation. Yet I favour "complex" syntax because it tends to be closer to natural language. So far I have failed to find a language which combines a powerful macro mechanism such as LISP's with a naturally looking syntax (1). Is anyone aware of such a language? Footnote: I would consider python to have a naturally looking syntax as it allows constructs like this: if 0 < a < 5 and b in list. The avoidance of braces to structure blocks is irrelevant in this case, though.

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  • Reduced Tree View in NetBeans IDE 7.2

    - by Geertjan
    Right-click within the Projects window in NetBeans IDE 7.2 and from the "View Java Packages As" menu, you can now choose "Reduced Tree".I never really understood the difference between "Reduced Tree" and the already existing "Tree". But it makes sense when you see it. Here's Reduced Tree view: And here's Tree view, where you can see that the "actions" and "nodes" packages above each have their own top level package nodes, which takes up more space than the above: What's cool is that your selected package view is persisted across restarts of the IDE. To be complete, here's the List view, which is the third option you have in the "View Java Packages As" menu: Seems to me like the new Reduced Tree view combines the best of the Tree view with the best of the List view! Related issue: http://netbeans.org/bugzilla/show_bug.cgi?id=53192

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  • Code-Golf: one line PHP syntax

    - by Kendall Hopkins
    Explanation PHP has some holes in its' syntax and occasionally in development a programmer will step in them. This can lead to much frustration as these syntax holes seem to exist for no reason. For example, one can't easily create an array and access an arbitrary element of that array on the same line (func1()[100] is not valid PHP syntax). The workaround for this issue is to use a temporary variable and break the statement into two lines, but sometimes that can lead to very verbose, clunky code. Challenge I know of a few of these holes (I'm sure there are more). It is quite hard to even come up with a solution, let alone in a code-golf style. Winner is the person with in the least characters total for all four Syntax Holes. Rules Statement must be one line in this form: $output = ...;, where ... doesn't contain any ;'s. Only use standard library functions (no custom functions allowed) Statement works identically to the assumed functional of the non-working syntax (even in cases that it fails). Statement must run without syntax error of any kind with E_STRICT | E_ALL. Syntax Holes $output = func_return_array()[$key]; - accessing an arbitrary offset (string or integer) of the returned array of a function $output = new {$class_base.$class_suffix}(); - arbitrary string concatenation being used to create a new class $output = {$func_base.$func_suffix}(); - arbitrary string concatenation being called as function $output = func_return_closure()(); - call a closure being returned from another function

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