modified-preorder-tree-t

How to generate a tree view from this result set based on Tree Traversal Algorithm?

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问题 I have this table: CREATE TABLE `categories` ( `id` int(11) NOT NULL auto_increment, `category_id` int(11) default NULL, `root_id` int(11) default NULL, `name` varchar(100) collate utf8_unicode_ci NOT NULL, `lft` int(11) NOT NULL, `rht` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `category_id` (`category_id`), KEY `lft` (`lft`,`rht`), KEY `root_id` (`root_id`) ) Based on this question: Getting a modified preorder tree traversal model (nested set) into a <ul> The difference is that I have many

How to generate a tree view from this result set based on Tree Traversal Algorithm?

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How to indicate preorder of a spanning tree using the algorithm BFS

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问题 I'm doing an implementation of the BFS algorithm in c++ to find a spanning tree, the output for a spanning tree should be shown in preorder, but I have a doubt in the implementation, how I can build a tree if not exactly know how many children have each node?. Considering a tree structure recursive The data structure of the tree can be written as: typedef struct node { int val; struct node *left, *right; }*tree; //tree has been typedefed as a node pointer. But do not think it works this

Modified preorder tree traversal: Selecting nodes 1 level deep

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问题 I have hierarchical ordered data saved using the modified preorder tree traversal algorithm. Here's tables content: id lft rgt name 1 1 10 topnode 2 2 3 level1 3 4 7 level1 4 5 6 level2 5 8 9 level1 Visualised: What I want is to select just the childnodes of a certain node (so not the childnodes of the childnodes). Let's say 'topnode'. I'm trying to fix a query, but I can't seem to get my head around it. Searching the internet brings me a while, for example: I can calculate the depth of each

Modified preorder tree traversal: Selecting nodes 1 level deep

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I have hierarchical ordered data saved using the modified preorder tree traversal algorithm. Here's tables content: id lft rgt name 1 1 10 topnode 2 2 3 level1 3 4 7 level1 4 5 6 level2 5 8 9 level1 Visualised: What I want is to select just the childnodes of a certain node (so not the childnodes of the childnodes). Let's say 'topnode'. I'm trying to fix a query, but I can't seem to get my head around it. Searching the internet brings me a while, for example: I can calculate the depth of each node, but I just can't seem to select on it. This query SELECT node.*, (COUNT(parent.id) - 1) AS depth

How to generate a tree view from this result set based on Tree Traversal Algorithm?

阅读更多关于 How to generate a tree view from this result set based on Tree Traversal Algorithm?

I have this table: CREATE TABLE `categories` ( `id` int(11) NOT NULL auto_increment, `category_id` int(11) default NULL, `root_id` int(11) default NULL, `name` varchar(100) collate utf8_unicode_ci NOT NULL, `lft` int(11) NOT NULL, `rht` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `category_id` (`category_id`), KEY `lft` (`lft`,`rht`), KEY `root_id` (`root_id`) ) Based on this question: Getting a modified preorder tree traversal model (nested set) into a <ul> The difference is that I have many trees in one table. Each row has a foreign key representing its parent and its top parent: category_id