Questions tagged [binary-search-trees]
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97
questions
0
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0answers
14 views
Parent Node in BST
Is it a good idea to store a pointer to the parent node in a binary search rather than to find the parent node several times?
...
0
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1answer
134 views
Remove range of keys from Binary Search Tree in O(s+h)
I have a binary search tree with integer keys. I have to remove a range (m, n]eZ of keys from the BST in O(s + h)
where s is the number of keys to remove and h is the height of the tree.
Attempted ...
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0answers
51 views
Calculate number of nodes in all subtrees without using DFS
Is it possible to calculate the number of nodes using post-traversal order, instead of using DFS?
Below is an illustration of the question:
0
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0answers
13 views
Data structure for revising ordering given a (largely) ordered stream of data
I have an input stream of timestamped data that is largely sorted in ascending order by timestamp. There are occasionally out-of-order elements, at which point I need to do each of the following:
...
1
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0answers
100 views
Algorithm to delete BST nodes with duplicated values
In a binary search tree the following must hold:
Greater keys are in the right-subtree
Smaller or EQUAL keys belong to the left-subtree
All the algorithms I found to delete a node start by finding ...
0
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0answers
29 views
How many Binary Search Trees are there which have N nodes and their height is log N
How many Binary Search Trees are there which have N nodes and their height is log N ? We need a recursive function to solve this problem. For example if n=2 the answer is 2. If n=3 answer is 1 . If n=...
0
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1answer
171 views
How to find time complexity of this pseudocode
Recently, I came across a question about finding sum of all values in range $[low, high]$ in BST $T$.
Then I formulated following algorithm to carry out that task:
We do inorder traversal of ...
1
vote
2answers
41 views
Inorder tree tranversal on binary search tree doesn't give the elements in order?
I have been told that inorder tree tranversal of binary search trees returns the tree elements in order. I came up with this binary search tree:
...
2
votes
0answers
38 views
Reasoning for awkward style of TreeMap.getHigherEntry
Consider a binary search tree (AVL, red-black, whatever). The goal "find the least key strictly greater than the specified one" ("upper_bound" in C++ STL, higherEntry//higherKey in Java, etc.) can be ...
0
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1answer
125 views
Constructing preorder traversal from postorder of a Binary Search Tree in O(n)
We are given postorder traversal of a Binary "SEARCH" Tree (in an array) and we want to find (print) its preorder traversal.
A very naive solution is to check from end until we find element less than ...
1
vote
1answer
34 views
question about the construction of BSTs using a repeated sequence of rotations
How can I show that any binary search tree can be balanced with at most O(n log n) rotations (“balanced” here means that the lengths of any two paths from root to leaf differ by at most 1).
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1answer
37 views
How to construct a perfect BST from an unbalanced BST with n elements (assuming that n=(2^i)-1, i is natural)
How do I construct a perfect BST from an unbalanced BST with $n$ elements (assuming that $n=2^i-1$, $i$ is natural). ** At the worst case of $O(n)$**.
2
votes
1answer
103 views
Height of epsilon-balanced binary search tree
In Balanced Binary Search Trees on the basis of size of left and right child subtrees, Hannes says:
For example, one can say, a BST is balanced, if each subtree has at
most epsilon * n nodes, ...
0
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1answer
159 views
Leaf nodes of B+ Tree
I have a b+ tree and i want to find the record associated with a specific key Ki.
So i run the b+ tree search algorithm. If a certain node in the search path is a leaf and K=Ki, then the record exists ...
0
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2answers
40 views
creating a binary search tree (manual)
I've been given the following values to add to a binary search tree (in the order given)
56, 35, 55, 58, 29, 15, 16, 5, 71, 92, 69, 95
and this is what my tree ended up like:
but apparently it's ...
-1
votes
2answers
32 views
post order for binary search tree
I got this as the post order sequence but the answer says it is wrong. I do get a bit confused with the post order logic as well.
8 11 10 9 13 16 18 15
2
votes
1answer
33 views
in order of binary search tree
This is what I got for the in-order of the bst but it's wrong because I'm answering some questions about some successors of some of the letters and I got them wrong. so I'm wondering where in this in-...
0
votes
1answer
240 views
How is the right, root, left order traversal called in a binary search tree?
In a Binary Search Tree you have the following orders for traversal:
Left, Root, Right is called Inorder (or ascending order).
Root, Left, Right is called Preorder.
Left, Right, Root is called ...
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2answers
1k views
Time complexity for balancing an unbalanced binary tree
The question here is that: There is an unbalanced binary tree with n-nodes. What is the time complexity to balance the tree?
The solution I thought of involved solving using Recursion where for the ...
0
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1answer
47 views
Is the tree shown a valid red-black tree?
I have made a red-black tree and I think that it is not valid. Could someone please verify?
As far as I know, in red-black tree we also consider the leaf nodes at the NULLS of the visible leaf nodes ...
0
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0answers
30 views
RB trees from any balanced BST?
Given any perfectly balanced binary search tree, is it always possible to assign a coloring to the nodes so that it becomes a Red-Black tree? If so, how do you prove this, and if false, what would be ...
0
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1answer
24 views
AVL tree balance property states for the two subtrees of a node, their height can differ at most one. Why can't it be zero?
I was thinking that if they were equal, say they are required to be zero this would be enforce the balance property more effectively. Can anyone explain why 1 is a satisfactory rather than just them ...
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vote
3answers
726 views
Why is Binary Heap never unbalanced?
My professor asks this question: Binary Search tree has Rotation Method to prevent it from degenerating into a linear structure (unbalanced tree). Why is there no need for such method for Binary Heaps?...
0
votes
1answer
69 views
Which binary search trees have constant time rebalancing time at min/max?
Given that I'm already at either the min or the max node of a binary search tree, which balanced variant would require only constant time bottom-up rebalancing after an update (add new min/max, or ...
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0answers
33 views
Finding Binary Search Tree Height, What happens to duplicates?
I'm going over past exam papers with this question:
The answer to a). will be (height of 5):
For b.):
I assume the height function will be to find the height of the tree. So, I will have to compare ...
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0answers
158 views
Tracing BST Pseudocode for Insertion
I'm having real trouble tracing some pseudocode for insetion into a Binary Search Tree. I need to understand this in order to be able to teach it, but I think there are flaws in the material.
For ...
0
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2answers
44 views
Algorithm for searching in BST with only <
How could one construct an algorithm for finding a node in a binary search tree that only requires the presence of $<$ on the key type. The ones I can easily also requires $=$.
0
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1answer
34 views
Augmenting a tree such that we preserve the insertion operation optimal runtime
Suppose we are given a red-black tree with $n$ vertices with distinct keys and we want to store, as addition information in each vertex $v$, the biggest key out of the keys that are smaller than $v$ (...
2
votes
1answer
164 views
Proof that a subtree of a red-black tree has no more than $\frac{3n}{4}$ nodes
I have a red-black tree with $n$ nodes, rooted at $x$. How can I prove or disprove that the number of nodes in any subtree of $x$ (including the root of the subtree) will never be greater than $\frac{...
0
votes
1answer
83 views
avl trees rotations question
As you can see in this tree its unbalanced at the root with a balanced factor of $-2$. You can also perform a Right left rotation or a Right Right rotation. Which do you have to pick in this case?
1
vote
1answer
130 views
fixing a slightly broken BST tree
I'm stuck on this question, a BST is slightly broken only if there is a node with value x in which :
there is at least one value less than x on its right branch or atleast one value greater than x on ...
1
vote
1answer
607 views
Binary Search Tree – Number of comparisons when element is not found
I am confused regarding Binary Search Trees (BST) when an element does not exist in the tree.
For example, to search for element "6", would it take 5 comparisons to search for this element?
My ...
1
vote
1answer
632 views
AVL Tree rotations : How to balance below AVL Tree with imbalance at root node
How to balance this AVL tree after inserting node 5, using left/right rotations as indicated in the AVL tree tutorial. I have tried applying both double rotations but with no luck. Either of the ...
1
vote
1answer
83 views
Searching in a Binary Search Tree
I'm studying Binary Search Trees (BST) and I would like to verify that my understanding of BSTs is correct.
For example, let S = [17, -10, 7, 19, 21, 23, -13, 31, 59].
Binary Search Tree for S, with ...
3
votes
3answers
127 views
BST - Sufficient condition for connecting a node to a parent
Let's assume that we have a binary search tree with node Y that hasn't a right child and for whom a successor exists in the tree.
I want to prove that if I insert a node X into the tree and node X is ...
2
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1answer
227 views
How to find the number of Binary Search Trees with given number of nodes and leaves?
With 7 nodes of distinct values (unique), how many Binary search trees (BST) can be formed such that:
Exactly $1$ leaf node(s) present?
Exactly $2$ leaf nodes present?
I was able to solve the first ...
1
vote
2answers
243 views
Deriving the average depth for a randomly generated binary search tree
If $D(n)$ is the internal path length (sum of the depths of all nodes) for some tree $T$ with $n$ nodes then we have the following recurrence relation: $$D(n)=D(i)+D(n-i-1)+N-1$$ where I simply taken ...
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2answers
1k views
Calculation of Inorder Traversal Complexity
I want to analyze complexity of traversing a BST. I directly thought that its complexity as $O(2^n)$ because there are two recursive cases. I mean $T(n) = constants + 2T(n-1)$. However, AFAI research ...
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1answer
151 views
All the possible inputs for a given AVL tree
Given an AVL tree,what are the possible inputs so that the same given tree is formed(please dont mention brute force technique)?
0
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1answer
73 views
The validity of the potential function for splay tree
The paper "Self-Adjusting Binary Search Trees" defines (Page 658) the potential function for analyzing the amortized cost of a sequence of $m$ splay operations as the sum of the ranks of all nodes in ...
3
votes
1answer
978 views
BST representation of Hash Tables
I'm reading this book Cracking Coding Interview. In this book author is speaking about BST representation of Hash Tables.
I googled a lot for BST Representation of Hash Table. Code in C++ but didn't ...
2
votes
1answer
2k views
Average height of a BST with n Nodes
I have to find the maximum, minimum, and average height of a BST with n nodes. After doing some researching I found that the maximum height is $n-1$ and the minimum height is $\log_2(n+1)-1$. My ...
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0answers
59 views
Upper bound on the average path length in binary search tree
I have been reading the chapter 6.2.2 in Knuth's book about lower and upper bound on the average path length in binary search tree.
And I have problems with understanding small details of Theorem M (...
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vote
0answers
55 views
Example of binary trees with maximum rotation distance
In the 1988 paper Rotation Distance, Triangulations, and Hyperbolic Geometry, Sleator, Tarjan and Thurston show that for any pair of $n$-node binary trees, the maximum rotation distance between them ...
2
votes
1answer
52 views
What is the average size of a jump in a binary tree?
Assume that a full binary tree is layed out in memory recursively in the following way.
First the Root followed by Tree representation of left subtree followed by tree representation of right subtree. ...
5
votes
2answers
1k views
If inorder traversal of a tree is in ascending order will the tree definitely be a BST?
For a binary search tree (BST) the inorder traversal is always in ascending order. Is the converse also true?
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0answers
24 views
Splay Tree - Insert Permutation
Let $T$ be a Splay Tree. For a given permutation $\sigma$ on a set $S = \{1,2,3,...n \}$ we defined the following function:
...
0
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1answer
97 views
Binary Tree Node Insertion
I was trying to implement a Binary Search Tree using this article as a reference: Binary Search Tree in JavaScript.
I was thinking especially about the node insertion method. Here's my ...
0
votes
1answer
281 views
All possible Red Black Trees with this set {1,2,3,4,5}
I have to write all possible Red Black Trees which can represent these 5 numbers {1,2,3,4,5}.
Now we have 120 ways to write 1,2,3,4,5
...
1
vote
1answer
203 views
how does rotation works in AVL trees and what is a good way to understand it?
If we consider this tree with T1 and T2 as subtrees, and we want to rotate on x (rotating the edge between T1 and x), what is the result? how does it work then? Does the x stay in its place and T1 ...
