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Questions tagged [binary-search-trees]

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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 ...
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2answers
34 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 $=$.
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1answer
28 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 $v$ (...
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1answer
27 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{...
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1answer
25 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?
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1answer
34 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 ...
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1answer
122 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 ...
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1answer
146 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 ...
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1answer
50 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 ...
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3answers
62 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 ...
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1answer
49 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 ...
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2answers
68 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
40 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
55 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)?
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1answer
51 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 ...
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1answer
74 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 ...
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1answer
408 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
48 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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0answers
26 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
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1answer
32 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. ...
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2answers
741 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
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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: ...
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1answer
70 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 ...
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1answer
149 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 ...
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1answer
53 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 ...
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4answers
920 views

Why use binary search trees when hash tables exist?

Hash tables perform lookup, insertion, and deletion in O(1) time (expected and amortized) while the different variants of binary search tree (BST) - treap, splay, AVL, red-black - offer at best O(log ...
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0answers
86 views

Time complexity proof of finding the $i$ object in binary search tree is $O(h+i)$ by inorder

I'm looking for time complexity proof of finding the $i$ object in binary search tree is $O(h+i)$ by inorder run. when $h$ is the height of the tree.
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1answer
559 views

Number of binary search trees with maximum possible height for n nodes

I'm using the definition of the height of a tree as the longest possible path from the root to a leaf by its number of edges, e.g. a tree of 2 nodes has a height of 1. With that in mind, what would ...
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1answer
54 views

Complexity for find pairs with sum - BST

I have written an algorithm for find all the pairs in a BST which have a given sum. ...
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0answers
26 views

Looped binary sorting tree

I want to add a points one by one into sorting tree. I have less then function to order them by angle from absciss: for points $\mathbf p_i = (x_i,y_i)$ and $\mathbf p_j = (x_j,y_j)$ it just sign of ...
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1answer
206 views

Simulating AVL Tree Right, then Left rotation

I have the following AVL tree and want to AVL-INSERT a node 5 into the tree. Since the middle branch will be unbalanced, I'm guessing that it will require a right rotation, then a left rotation to ...
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1answer
27 views

k-means clustering with efficient point lookup?

What's an algorithm for $k$-means clustering, in particular an online algorithm (you can stream new points to it), such that once the size of the set of clusters $k$ becomes large, we can still ...
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1answer
368 views

Time complexity of creating the unique binary tree from given inorder and preorder (or postorder) traversal sequences

Given inorder and preorder (or postorder) traversal sequences of a binary tree balanced binary tree binary search tree of n nodes, what is the time complexity of creating the respective unique tree.
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157 views

How many similar binary search trees are made from different permutations?

If I have numbers ranging from 1 to n, and I generate all the permutations of these numbers. Now, I create Binary search tree from these permutations. For a value n i want to know how many BSTs would ...
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1answer
28 views

Generate a unique number for a set of sequences of letters

A sequence of English letters are given, every sequence forms a word and we know that the size of each word is at most $15$ and the number of words is at most $50000$. For a given input word $w$ I ...
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0answers
30 views

AVL Tree Inner Nodes

If k is the height of an AVL Tree, the minimal number of inner nodes is: N(k) = N(k-1) + N(k-2) +1. Why is this formula true?
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1answer
746 views

Which of the following sequences could not be the sequences of nodes examined in a binary search tree?

Suppose that we have numbers between $1$ and $1000$ in a binary search tree and want to search for the number $363$. Which of the following sequences could not be the sequences of nodes examined <...
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2answers
2k views

Time complexity of searching an element in Binary Search Tree [closed]

I want to know what will be the time complexity to search, insert and delete an element in a) balanced binary search tree. b) unbalanced binary search tree.
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1answer
274 views

Rooted Binary Tree - Chain Nodes Algorithm

The question is that I have to give a recursive algorithm in pseudocode, that counts the number of chain node in a rooted binary tree. Chain node is defined as a node that has only one child and that ...
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0answers
94 views

An AVL tree is a BST, but AVL tree can be not complete, then why do we define AVL tree a BST?

An AVL tree is a BST, and a BST is a complete tree, but AVL tree doesn't necessarily have to be complete. Thus, why do we define AVL tree a BST?
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1answer
160 views

Is there an example of an AVL tree that is taller than a binary heap?

I am curious because I took a quiz and answered false to the question: "The height of an AVL tree may be greater than the height of a binary heap with the same elements." I have been trying to think ...
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1answer
403 views

When to rebalance the AVL tree?

Consider we have an AVL tree. Its left subtree A has disbalance coefficient has value +1 (meaning the right subtree has greater depth). Its right son has disbalance coefficient -1 (meaning left ...
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0answers
35 views

Read nodes of a BST in blocks of size $k$ and traverse it in $\mathcal{O}(log_kn)$

This describes how one can neatly store a binary search tree as an array. I'm looking for a way to store a BST that will allow me to traverse any root to leaf path by loading $\mathcal{O}(log_kn)$ ...
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1answer
43 views

Randomized BST height analysis : How $Z_{n,i}$ and $Y_{k-1}$ are independent?

I am referring to this video https://www.youtube.com/watch?v=vgELyZ9LXX4 at 1:08:39 . $n$ : number of nodes in the tree $Z_{n,k}$ : Indicator random variable that activates when rank of the root ...
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0answers
588 views

Day-Stout-Warren algorithm for balancing BST. How does vine to tree work?

I was trying to understand the dsw algorithm for balancing a binary search tree in-place using this virgina tech page. The wikipedia page and vt page are more or less similar. I am having a hard time ...
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2answers
290 views

Balanced Binary Search Tree Two-Sum with Constraints

My question spawns from this question. The question is straightforward: Can we find whether there exist 2 values in a balanced binary search tree where their sum equals a given target value? Now ...
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0answers
300 views

How to find point of maximum overlap in both X and Y Axis?

I was given a array R of n rectangles [each element in the array is a bottom left point(x1,y1) and a top right point (x2,y2)] , parallel to the axis, and an array P of n points [each element is a ...
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0answers
106 views

What would be the probabilty of a randomly generated tree to be a Red-Black Tree

The question is not related to the homework I was working on a homework, and the specification was to generate a random tree with n elements(n being in the thousands for the assignment) and asked me ...
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1answer
415 views

Data structure for handling intervals

I am trying to create a data structure for handling the subsets of the real line of the form $[x,y)$. That is, suppose $X \subseteq \mathbb{R}$ and the data structure supports two types of operations: ...
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0answers
29 views

Binary Search Tree: If two different traversals are given, will there be a unique tree that satisfies the traversals? [duplicate]

I have come across algorithms that can create a BST if any two of the 3 traversals are given (there would be three different algorithms for the 3 combinations) This is an example I was wondering, is ...