traversal

问题 I am trying to ensure a global correct orientation of my normals. I.e make sure they point outwards everywhere. This is my method: I have a coordinate list x y c n . At each point in coordinate list I create edges from the point to its 5 nearest neighbours. I Weight each edge with ( 1-n1.n2 ). Compute a minimal spanning tree. Traverse this tree in depth first order. Start traversing at the point with the greatest z value, force the normal of this point to be orientated towards the positive z

问题 My problem is as follows: I have a binary search tree with keys: a1<a2<...<an , the problem is to print all the (a_i, a_i+1) pairs in the tree (where i={1,2,3,...}) using a recursive algorithm in O(n) time without any global variable and using O(1) extra space. An example: Let the keys be: 1,2, ..., 5 Pairs that will be printed: (1,2) (2,3) (3, 4) (4, 5) So you can't do inorder traversal in the tree and find the successor/predecessor for each node. Because that would take O(nh) time and if

问题 I have a directory containing some files, some directories, some symlinks to files and some symlinks to directories. When I do os.walk() with followlinks=false in the directory, I get the files and symlinks to files in the filenames list and the directories in the dirnames list. But the symlinks to directories does not show up anywhere. Is this a bug or a feature in Python, or am I doing something wrong? I expect the symlinks to directories to show up in the filenames list, because they are

问题 I faced that simply iterating through MSHTML elements using C# is horribly slow. Here is small example of iteration through document.all collection three times. We have blank WPF application and WebBrowser control named Browser: public partial class MainWindow { public MainWindow() { InitializeComponent(); Browser.LoadCompleted += DocumentLoaded; Browser.Navigate("http://google.com"); } private IHTMLElementCollection _items; private void DocumentLoaded(object sender, NavigationEventArgs e) {

问题 How can I generate a tree with an unknown number of nodes, each of which have an unknown and varying number of children, with the condition that a list of the child nodes for a given parent node is generated by some fun(parent)? Note that I'm using library(data.tree) from cran to make my tree hierarchy. The tree will always begin with a node defined by a given parent vector. There will always be a finite amount of nodes. Every node will have the same length as the root node. I've tried to

问题 I wanted to add and event listener to a button and I am still relatively new on coding purely on javascript, so I don't know what are the native equivalent of $this in my code // the markup <ul class="menu"> <li><a href="#" data-something="value">text</a></li> <li><a href="#" data-something="value2">text2</a></li> </ul> var menu = document.querySelector(".menu"); menu.addEventListener("click", function(){ // console.log $(this).val // what I wanted is to get that data-attribute of the clicked

问题 I am trying to learn DFS by creating a program that navigates my ogre through a maze (2d array).This is similar to a dailyprogramming challenge, but I am doing it with just a 1x1 ogre. My maze: static int[][] maze = { {2,1,0,0,0,0,0,0,0,0}, {0,0,1,0,0,0,0,0,0,0}, {1,0,0,0,0,1,0,1,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,1,1,0,0,0,0,0,0}, {0,0,1,0,0,0,0,1,0,1}, {1,1,0,0,0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0}, {0,0,0,0,0,1,1,0,0,0}, {0,0,0,0,0,1,0,0,0,3}}; Where 2 is my hero (0,0), 3 is my goal (9,9), 1s

问题 I have written the following code for constructing a tree from its inorder and preorder traversals. It looks correct to me but the final tree it results in does not have the same inorder output as the one it was built from. Can anyone help me find the flaw in this function? public btree makeTree(int[] preorder, int[] inorder, int left,int right) { if(left > right) return null; if(preIndex >= preorder.length) return null; btree tree = new btree(preorder[preIndex]); preIndex++; int i=0; for(i

问题 I am trying to adapt Brian's Fold for Bianary Trees (http://lorgonblog.wordpress.com/2008/04/06/catamorphisms-part-two/) to apply for Multiway trees. Summarizing from Brian's Blog: Data structure: type Tree<'a> = | Node of (*data*)'a * (*left*)Tree<'a> * (*right*)Tree<'a> | Leaf let tree7 = Node(4, Node(2, Node(1, Leaf, Leaf), Node(3, Leaf, Leaf)), Node(6, Node(5, Leaf, Leaf), Node(7, Leaf, Leaf))) Binary Tree Fold function let FoldTree nodeF leafV tree = let rec Loop t cont = match t with |

问题 a little out of my depth here and need to phone a friend. I've got a directed acyclical graph I need to traverse and I'm stumbling into to graph theory for the first time. I've been reading a lot about it lately but unfortunately I don't have time to figure this out academically. Can someone give me a kick with some help as to how to process this tree? Here are the rules: there are n root nodes (I call them "sources") there are n end nodes source nodes carry a numeric value downstream nodes