traversal | 易学教程

Is there more to optimizing CSS than minimizing character count?

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问题 I've been reading a lot about jQuery optimization and how you can alter your selectors to cut down on the amount of DOM traversal, but I haven't heard much about CSS optimization outside of the usual minifying process. Is there any way to optimize your CSS loading/processing outside of just reducing character count and server requests? 回答1: You can definitely optimise your selectors for performance. One key point is that CSS parsers read selectors right to left, whereas javascript selector

Finding all possible paths in graph

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问题 I'm looking for some algorithm which will help me find all possible paths in a graph. Everything I found so far is not fully satisfying. Let's imagine we have a graph (tree) like this one: And let's use some algorithm like Breadth-First Search or Depth-First Search . In return we'll get something like 1, 2, 4, (2), 5, (2), 6, (2), (1), 3, 7, 8, (7), 9 Which is how we go through this tree and this is not what I'm looking for. I'd love to get all paths, like: 1 1, 2 1, 2, 4 1, 2, 5 1, 2, 6 1, 3

How to Traverse a N-Ary Tree

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问题 My Tree/Node Class: import java.util.ArrayList; import java.util.List; public class Node<T> { private T data; private List<Node<T>> children; private Node<T> parent; public Node(T data) { this.data = data; this.children = new ArrayList<Node<T>>(); } public Node(Node<T> node) { this.data = (T) node.getData(); children = new ArrayList<Node<T>>(); } public void addChild(Node<T> child) { child.setParent(this); children.add(child); } public T getData() { return this.data; } public void setData(T

How to skip subtrees in AST traversal using python bindings for libclang

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问题 I have just started using libclang via python bindings. I understand that I can traverse the entire syntax tree (AST) using get_children , but I have not been able to find a get_next_sibling() (or whatever it might be called) function so that I can skip subtrees that are not of interest. Does such a function exist? 回答1: I don't think a get_next_sibling function exists in the Python API, but I also don't see why you should need it. In the python API, each node in the AST knows about all its

Attach javascript/jquery event on dynamically created elements

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问题 I've seen a lot of different questions similar to this, but all of them generally targeted a specific selector. Please let me know if there is a duplicate somewhere and I've missed it. Take this scenario: You want to build a jquery plugin for a wordpress, drupal, or basically any site that uses third party functionality. Since you don't know ahead of time every specific event and selector you will need to target how would you add jquery/javascript functionality to elements that are created

How can I find all text nodes between two element nodes with JavaScript/jQuery?

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问题 Given the following HTML-Fragment: <div> abc [ def ghi jkl ] mno </div> I need an algorithm to fetch all nodes of type Text between #x and #y with Javascript. Or is there a JQuery function that does exactly that? The resulting Text nodes (whitespace nodes ignored) for the example above would then be: ['def', 'ghi', 'jkl'] 回答1: The following works in all major browsers using DOM methods and no library. It also

How to traverse stack in C++?

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问题 Is it possible to traverse std::stack in C++? Traversing using following method is not applicable. Because std::stack has no member end . std::stack<int> foo; // .. for (__typeof(foo.begin()) it = foo.begin(); it != foo.end(); it++) { // ... } 回答1: Is it possible to traverse std::stack in C++? No. A stack is a data structure you should use when you are interested in placing elements on top and getting elements from the top. If you want an iterable stack, either use a different data structure

Printing Successor and Predecessor in a BST

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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 the tree is balanced, it will be O(nlgn) for the whole tree. Although you are right that finding an in

Understanding the logic in iterative Postorder traversal implementation on a Binary tree

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I was trying to understand how it is so intuitive to implement postorder traversal using 2 stacks. How did someone come up with it, is it just an observation or some particular way of thinking which helps one come up with such methods. If yes then please explain how to think in the right direction. Let me explain how I stumbled on the solution: You start off with this simple observation: prima facie, the pre-order and post-order traversal differ only in their order of operations : preOrder(node): if(node == null){ return } visit(node) preOrder(node.leftChild) preOrder(node.rightChild)

What's wrong with my tree traversal code?

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I have a simple tree, defined thusly: type BspTree = | Node of Rect * BspTree * BspTree | Null I can get a collection of leaf nodes (rooms in my tree "dungeon") like this, and it seems to work: let isRoom = function | Node(_, Null, Null) -> true | _ -> false let rec getRooms dungeon = if isRoom dungeon then seq { yield dungeon } else match dungeon with | Node(_, left, right) -> seq { for r in getRooms left -> r for r in getRooms right -> r } | Null -> Seq.empty But now I'm trying to get sister leaf node rooms so I can connect them with corridors, and I'm failing miserably (as I often do). Here