A Tree is just a restricted form of a Graph. Trees have direction (parent / child relationships) and don’t contain cycles. They fit with in the category of Directed Acyclic Graphs (or a DAG). So Trees are DAGs with the restriction that a child can only have one parent. One thing that is important to … Read more
Store IDs of the objects in a hash table mapping to the specific object. Enumerate through all the objects and find their parent if it exists and update its parent pointer accordingly. class MyObject { // The actual object public int ParentID { get; set; } public int ID { get; set; } } class … Read more
DFS: list nodes_to_visit = {root}; while( nodes_to_visit isn’t empty ) { currentnode = nodes_to_visit.take_first(); nodes_to_visit.prepend( currentnode.children ); //do something } BFS: list nodes_to_visit = {root}; while( nodes_to_visit isn’t empty ) { currentnode = nodes_to_visit.take_first(); nodes_to_visit.append( currentnode.children ); //do something } The symmetry of the two is quite cool. Update: As pointed out, take_first() removes and … Read more
There is an efficient solution if you use a map-lookup. If the parents always come before their children you can merge the two for-loops. It supports multiple roots. It gives an error on dangling branches, but can be modified to ignore them. It doesn’t require a 3rd-party library. It’s, as far as I can tell, … Read more
All these data structures are used for solving different problems: Segment tree stores intervals, and optimized for “which of these intervals contains a given point” queries. Interval tree stores intervals as well, but optimized for “which of these intervals overlap with a given interval” queries. It can also be used for point queries – similar … Read more
To see a tree view in recent versions of Chrome: Navigate to Developer Tools > Network > the given response > Preview
I recommend anytree (I am the author). Example: from anytree import Node, RenderTree udo = Node(“Udo”) marc = Node(“Marc”, parent=udo) lian = Node(“Lian”, parent=marc) dan = Node(“Dan”, parent=udo) jet = Node(“Jet”, parent=dan) jan = Node(“Jan”, parent=dan) joe = Node(“Joe”, parent=dan) print(udo) Node(‘/Udo’) print(joe) Node(‘/Udo/Dan/Joe’) for pre, fill, node in RenderTree(udo): print(“%s%s” % (pre, node.name)) Udo … Read more
Binary tree: Tree where each node has up to two leaves 1 / \ 2 3 Binary search tree: Used for searching. A binary tree where the left child contains only nodes with values less than the parent node, and where the right child only contains nodes with values greater than or equal to the … Read more
I learned that depth and height are properties of a node: The depth of a node is the number of edges from the node to the tree’s root node.A root node will have a depth of 0. The height of a node is the number of edges on the longest path from the node to … Read more
There are two reasons you could want to use a tree: You want to mirror the problem using a tree-like structure: For this we have boost graph library Or you want a container that has tree like access characteristics For this we have std::map (and std::multimap) std::set (and std::multiset) Basically the characteristics of these two … Read more