6,396 questions
1
vote
2
answers
86
views
Correctness of Algorithm: Convert Sorted Array to Height Balanced BST
I was working on Leetocde 108: Convert Sorted Array to Binary Search Tree.
The input is a sorted array of integers, and the goal is to return a height-balanced binary search tree (BST), meaning that ...
- 11
-7
votes
2
answers
176
views
Lowest common ancestor C++ [closed]
I have been trying to solve this problem as a beginner in C++:
The problem is that, when using AI, it almost always provides an answer that is way too complex in both syntax and logic. When I prompt ...
- 33
Advice
0
votes
11
replies
104
views
Where do I find scapegoat trees real code?
The original article on scapegoat trees by Galperin and Rivest is quite interesting, and so seem to be all the courses, lectures, and descriptions, like OpenDataStructures and also with a lesson in ...
- 433
Advice
0
votes
6
replies
162
views
What is the best way to get into coding?
I would like to start computer science courses at my University soon and I want to be prepared. Best recommendations? Free or paid is alright. If you could link an IRL, I have a personal computer ...
0
votes
0
answers
195
views
How to use index in simple select
Table has index on name column:
CREATE TABLE firma2.klient
(
kood character(12) primary key,
nimi character(100),
...
);
CREATE INDEX IF NOT EXISTS ...
- 28.3k
4
votes
3
answers
251
views
Efficient ways to check if two binary trees are the same
I implemented a recursive solution in Python to check if two binary trees are identical, which traverses nodes recursively and compares values and structure. The time complexity is O(n), space O(h).
...
- 724
0
votes
0
answers
50
views
How do I display my BST using my preorder() and inorder() methods?
I'm doing a programming assignment for my class. One of my programs includes creating a BST with Python within a BST class, and I'm trying to display using preorder() and inorder() functions. My ...
- 1
6
votes
2
answers
266
views
Prefer container::lower_bound to std::lower_bound?
I understand that container::lower_bound harness helpful invariant of the very container hence gives a better performance than std::lower_bound.
Taking std::set::lower_bound as an example, during my ...
- 2,311
1
vote
1
answer
128
views
How to implement insertion into BST iteratively in Rust?
I'm trying to implement an algorithm for insertion into BST (binary search tree) in Rust. I did it recursively, but am having problems implementing the iterative solution. I'm struggling to borrow a ...
- 7,071
-1
votes
1
answer
77
views
What form of recursion is occurring in the "insert "and "list_all" methods of this code?
I am struggling to understand the recursion going on in the insert, _insert_recursive and _inroder_traversal methods. For context, I know recursion and the concept is not strange to me, I struggle to ...
- 1
0
votes
1
answer
95
views
understanding a part of recursion for a binary search tree
Hello I basically need to implement a recursive function for insertion of a binary tree. I already implemented the chunk of insertion function (wether it's largest or smaller than root) but there's an ...
- 11
3
votes
1
answer
874
views
Difficulty setting up threaded BST in C++
I'm having trouble implementing a threaded Binary Search Tree in C++. I have a non-threaded tree completely implemented (see below code). What I'm having difficulty with is setting the threads to ...
- 520
0
votes
0
answers
65
views
Error When Mutably Borrowing a Value From a Struct That Has Been Mutably Borrowed
Explanation
I'm attempting to implement a binary search tree in Rust. The problem is in the insert method, where I have a &mut Box<Node<T>> called node_to_insert_at. To insert the ...
- 23
0
votes
2
answers
123
views
Binary search tree memory leak adding residual child nodes to new trees
I'm having two issues with my code; I'd post them as two separate questions, but I believe one is causing the other. The first involves insertion; from my amateur eyes, the insert code seems to be ...
2
votes
2
answers
127
views
Self-balancing binary search tree and duplicated keys
I've implemented a red-black tree (which is a kind of self-balancing binary search trees) with duplicated keys allowed. In the Insert method I put nodes with equal keys as right child nodes. As you ...
- 2,184
0
votes
0
answers
37
views
Optimizing frequent deletions in a BST: AVL vs. Red-Black Tree?
I am working on optimizing the Delete-Max operation in an unbalanced Binary Search Tree (BST) where frequent max deletions occur. The current approach follows:
Traverse to the rightmost node.
Remove ...
1
vote
1
answer
69
views
Maximum difference between node and its ancestor Java soltion having issue
I am practicing Maximum difference between node and its ancestor Java problem using my own solution which worked fine for smaller test cases. However, this is giving differnt output than expected for ...
2
votes
1
answer
237
views
Data structure for easily finding the maximum length of a non-decreasing sequence on a certain interval
I'm trying to find a solution for this challenge:
Given is n, which is the size of an array filled with ones. There are two types of operations possible on this array:
Increase (x, y, m): add m to ...
- 31
0
votes
1
answer
139
views
solution to factorial problem using dynamic programming resulting in more time than simple recursion
I was just starting out with dynamic programming and tried solving factorial problem using the same, i used binary tree for underlying data structure, but when i thought of comparing it with normal ...
1
vote
0
answers
46
views
Removing Root Node from a BST?
I build my tree in main with a for loop adding nodes 1-15, removing say 5 or 15 work fine, i think my problem lies in removing the root. It wont follow pre-order when I call it after removing 1, i ...
0
votes
0
answers
45
views
What am I missing ? BST hidden case failure
Some hidden test cases fail to output correctly. I've tested for all edge cases I can think of; what am I missing?
Edge Cases Tested:
Nonexistent Key Deletion: Assumes input is valid per the problem ...
0
votes
1
answer
77
views
Segmentation fault for inserting into an BST
So for this class here, I have to write out functions, including a recursive find function, an insert function, and a operator[] function, which overall helps insert into a BST
#include <compare>...
- 11
1
vote
0
answers
73
views
Pointer inconsistency in modified Queue struct template using AVL
I'm making a modified Queue struct template using AVL tree to allow for moving elements forward. If I use normal linked list implementation, moving a given element forward by x positions will cos O(n),...
3
votes
4
answers
316
views
Can a recursion with nested calls in tail position be tail recursion?
Can a recursion with nested calls in tail position be tail recursion?
For example, I have the following function in Racket that is intended to convert a binary tree, defined as a nested struct below, ...
- 10.1k
3
votes
1
answer
169
views
Convert a sorted array into a height-balanced binary search tree by picking middle element -- why does it work?
I was doing an exercise to convert a sorted array to a binary search tree where every node in the tree has its children whose heights at most differ by 1.
One simple solution is to pick out the middle ...
- 10.1k
0
votes
1
answer
43
views
Red Black Tree | is this tree balanced?
I have recently begun studying the structure of the red-black tree and am struggling to determine whether it is balanced. And explain why it is still balanced, or vice versa.
...
- 3
2
votes
1
answer
203
views
Is the inorder predecessor of a node with no left subtree and being the left child of its parent always its grandparent?
I'm trying to understand the rules for finding the inorder predecessor of a node in a binary search tree (BST).
If a node 𝑥 has a left subtree, the inorder predecessor is the
largest value in that ...
- 49
1
vote
1
answer
205
views
Is the Inorder Predecessor of a Node with a Left Subtree Always a Leaf Node in a Binary Search Tree?
In a Binary Search Tree (BST), I am trying to understand the properties of the inorder predecessor, particularly for nodes that have a left subtree.
Definition: The inorder predecessor of a node is ...
- 49
-1
votes
1
answer
153
views
Binary Search Tree javascript Array - Data Structures
I am trying to build a binary tree with a array. I want to take the array, find the root and split right and left side, then perform the same split on each side if needed until two numbers are left ...
0
votes
1
answer
58
views
How can an AA-Tree always have 2 children per non-leaf node for arbitrary total-element counts?
I've been reading up on AA-Trees. One of their invariants is that every non-leaf node has two children. How can that work whenever the total element count happens to not be one less than a power of ...
- 2,082
0
votes
0
answers
112
views
How do you insert an interval into a disjoint segment tree in Haskell?
I don't think this is standard terminology, but we will define a "disjoint segment tree" as a segment tree (a flavor of binary search tree) whose values are pairwise-separated intervals (a,b)...
3
votes
1
answer
146
views
Correctness of Deletion algorithm of BST in CLRS
It's not quite obvious to me why the algorithm (see below) to delete a node from a binary search tree, that CLRS offers, works correctly (like how do we know that the inorder arrangement of the nodes ...
0
votes
1
answer
109
views
How is the one-bit AA Tree designed?
In the original "Balanced Search Trees Made Simple" paper by Arne Andersson, the first paragraph of the second chapter mentions that a single bit could be the flag before introducing the ...
- 2,082
1
vote
0
answers
62
views
Binary Search Tree remove node, sometimes it works, sometimes it doesnt
I'm currently working on the odin project on Binary Search Tree. I'm trying to make deleteNode work, and I'm working on removing a node if it is a leaf node.
Here's my code:
class Node {
...
- 13
2
votes
1
answer
118
views
Does this algorithm for converting a Binary Search Tree into a sorted linked list on Wikipedia have a bug in it?
I wanted to get a sanity check here. I believe the algorithm listed on the wikipedia page for the Day–Stout–Warren algorithm for balancing BSTs has a problem.
This pseudocode purports to turn a BST ...
- 8,439
2
votes
1
answer
125
views
Why is it impossible to convert a Min Heap to a Binary Search Tree (BST) in O(n) time?
I'm working on formally proving that it's impossible to convert a Min Heap into a BST in O(n) time complexity.
My reasoning is that any algorithm attempting this conversion would need to perform ...
- 23
-1
votes
1
answer
95
views
Binary Search Tree Insertion Method in Java [closed]
In the following insert method for a binary search tree (BST), the left side of the tree is being updated correctly, but there is an issue with inserting values on the right side. Despite using the ...
- 11
1
vote
1
answer
102
views
Fast Random Access, Update, Insert, Delete Data Structure [closed]
I want an ordered index-able data structure like a python list, which can access, update, insert and delete at arbitrary indices efficiently.
I have modified a skip list and an AVL tree to do the ...
0
votes
0
answers
30
views
Unexpected values in HashSet before method invocation in Java
package main;
import java.io.*;
import java.util.*;
public class IsBSTTree {
Set<Integer> set = new HashSet<>();
public static void main(String[] args) throws IOException {...
1
vote
1
answer
41
views
How can I get array output instead of memory location when printing TreeNode?
I am looking at solutions of LeetCode problem 108. Convert Sorted Array to Binary Search Tree:
Given an integer array nums where the elements are sorted in ascending order, convert it to a height-...
- 13
-2
votes
1
answer
126
views
Morris traversal leads to exception on LeetCode: address sanitizer , stack overflow [closed]
I have implemented a Morris traversal to solve LeetCode problem 98. Validate Binary Search Tree:
Given the root of a binary tree, determine if it is a valid binary search tree (BST).
My code
/**
* ...
0
votes
1
answer
118
views
(Scheme) Having trouble with binary search tree in-order traversal
I'm trying to write a Scheme program that performs an in-order traversal of a binary search tree:
(define (inorder lst)
(cond
((null? lst)
'())
((not (pair? lst))
(list lst))
...
1
vote
1
answer
114
views
What is the importance of implementing binary search trees (BST) for our database?
Binary search trees (BST) are helpful to perform CRUD operations efficiently. Do we need to implement a BST in a programming language when storing data in a database?
For example, consider Django + ...
- 57
0
votes
5
answers
195
views
why this code's return value doesn't cover all control path?
TreeNode* searchBST(TreeNode* root, int val) {
if(root==nullptr)return nullptr;
if(root->val==val)return root;
if(root->val<val)return searchBST(root->right,val);
...
- 11
1
vote
1
answer
127
views
Hashmap using Binary search tree incorrect implementation?
I'm doing some leetcode practice https://leetcode.com/problems/design-hashmap/description/ trying to implement a hashmap in C++ using a binary search tree as the underlying data structure. I'm passing ...
- 139
0
votes
1
answer
63
views
What is wrong with my approach of finding an indorder predecessor of a binary search tree?
void inorderPredecessor(Node* root, Node* &pre,int key){
if(root == NULL ) return ;
if(root -> data == key){
inorderPredecessor(root ->left , pre , key);
}else if(root -&...
- 25
1
vote
1
answer
206
views
Trying to understand how to search a BST with a given input
I am trying to figure out how to search a BST via a given input. The nodes in the tree have a randomly generated number as the key, and the value of the node is an object with various attributes.
...
- 21
2
votes
1
answer
91
views
Implicit Treap building time in O(n) time
I have two algorithms to build an implicity from an array, one is continuously merging
Like so:
public Node nlognConvertToTreap(int[] arr){
Node node = Node.EMPTY_NODE;
for (int x : arr) node =...
1
vote
0
answers
83
views
Cartesian tree index
input
The first line of the input file contains an integer number N -- the number of pairs you should build cartesian tree out of (1 ≤ N ≤ 50 000). The following N lines contain two numbers each -- ...
- 11
0
votes
1
answer
55
views
BST Delete node method removes entire subtree. Python
I'm struggling getting my Delete function to work for my BST class, I mostly understand the idea behind but can't quite get the implementation right.
Here in DataStructures.py I have a class for the ...
- 1