preorder

问题 When I am trying to print level Order of BST, this question prompted me. Here is a Pre-Order Sequence: 4, 1, 2, 3, 5, 6, 7, 8 In_order Sequence : 1, 2, 3, 4, 5, 6, 7, 8 A level order sequence for a BST with above pre_order and In_order is [4, 2, 6, 1, 3, 5, 7, 8] However, for the same Pre-order an In-order sequence this level order sequence seems possible. [4, 1, 5, 2, 6, 3, 7, 8] . I don't know how. I am trying to figure this out. I am unable to construct BST in paper (drawing) that

问题 I'm supposed to traverse a Binary Seach Tree as preorder, inorder and postorder and insert the values into an Object[] in Java. I honestly have no clue how to do this and I need some advice. My function: public Object[] traversePreOrder() All I need are basically some ideas or hints on how to complete this task. If I traverse a tree as preorder Object[0] is obviously the value of the root. Then I continue in the left tree and insert the most left values in my array. Next I insert the right

问题 I have a vector based binary tree and need to apply a function to each value in the tree using various methods of traversal. The preorder traversal was very easy to implement with a recursive function but I have been having trouble doing the same with the inorder and postorder traversals. If anyone could help out that would be great! Some extra information that I should have included: I am using a vector of nodes, each node containing a boolean variable stating whether or not that node is

问题 Check if 2 tree nodes are related (i.e. ancestor-descendant) solve it in O(1) time, with O(N) space (N = # of nodes) pre-processing is allowed That's it. I'll be going to my solution (approach) below. Please stop if you want to think yourself first. For a pre-processing I decided to do a pre-order (recursively go through the root first, then children) and give a label to each node. Let me explain the labels in details. Each label will consist of comma-separated natural numbers like "1,2,1,4,5

问题 Recently, my questions were marked duplicate, like this , even if they weren't. So, let me start with following and then I'll explain my question. Why this question is not a duplicate? I'm not asking how to create a binary tree when inorder & preorder traversal are given. I'm asking for the proof, that inorder+preorder traversal define a unique binary tree. Now, to original question . I went to an interview and interviewer asked me this question. I was stuck and couldn't proceed. :| Question:

问题 I realized recently that while having used BST's plenty in my life, I've never even contemplated using anything but Inorder traversal (while I am aware of and know how easy it is to adapt a program to use pre/post-order traversal). Upon realizing this, I pulled out some of my old data-structures textbooks and looked for reasoning behind the usefulness of pre-order and post-order traversals - they didn't say much though. What are some examples of when to use preorder/postorder practically?

问题 Here are key methods I wrote for converting linkedList to Balanced BinarySearch Tree . I get BST but it is not balanced. why is it so? public static Node headNode; public static IntTreeNode convertLinkedListToBST(Node node){ int len = getCount(node); headNode = node; return convertLinkedListToBSThelper(node, 0, len-1); } //http://www.programcreek.com/2013/01/leetcode-convert-sorted-list-to-binary-search-tree-java/ public static IntTreeNode convertLinkedListToBSThelper(Node node, int start,

问题 I am having some trouble understanding the recursive functions involved in preorder, inorder, and postorder tree traversal. I have some knowledge of recursion (but admittedly its not my strong suit). All of the seem to call themselves twice first making a call with the left child of the root and then with the right child. But how exactly is this possible? Wouldn't the call to the preOrder function with the left child return the flow of control back to the top, and the next call would never be

问题 Im trying to solve this problem:" A binary tree is given, check his pre-order visit and build a binary search tree with the same pre-order visit. Demonstrate if it is always possible, if not give an example when this is not possible." Any help? I need to write pseudocode and give time complexity but i have a lot of doubts about building a binary-search-tree with the same pre-order visit for every possible binary tree. 回答1: If you are using the classic algorithm for inserting in a binary

问题 Is there any way to print the pre-order traversal of the output given by MST (using Kruskal or Prim's algorithm). I have a confusion because the output may be or not a binary tree always. So, how the pre-order traversal is possible here? Can a normal DFS do the task? 回答1: The main issue when working with this kind of problem is the ambiguity of the word tree in algorithmic problems. There are two main definitions (those may in fact differ slightly): A tree is an acyclic connected (undirected)