Questions tagged [stack]

A stack is a last in, first out (LIFO) abstract data type and data structure. Perhaps the most common use of stacks is to store subroutine arguments and return addresses.

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6
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5answers
105 views

Safe stack abstraction

Here is the stack abstraction that I've written. I've designed it to be safe and without undefined behavior. I use ugly_cast to discourage casting and to make ...
12
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5answers
3k views

Stack class in Java 8

I have a exercise where I have to write a Stack class with the push and pop methods. The code compiles and works as it should. Are there better practices to use in my code? Is there something I should ...
4
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2answers
80 views

Basic Stack in C++ Using Array

I wrote a stack class in C++ using arrays of fixed width. Could anyone review my code ? I didn't comment on any of the functions, because I thought class itself is self explanatory. Is it a wrong ...
5
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2answers
96 views

Bracket balance checker in Python

Implement a feature for a text editor to find errors in the usage of brackets in the code. Input: sorted(list(zip(a, b)) Output: False Input: ([{}, {}]) Output: True Here's my implementation in ...
5
votes
3answers
74 views

Unix tail command using stack

I'm working on a version of the Unix tail command that works by iterating over a file, pushing line by line into a stack. Finally, the number of desired lines will be popped and printed to the screen. ...
8
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3answers
2k views

HackerRank Implement Queue using two stacks Solution

Challenge Problem Statement - Implement a Queue using two Stacks I implemented dequeue() in \$O(1)\$ at the cost of enqueue() ...
3
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3answers
617 views

JavaScript Sort Stack Coding Challenge

A coding challenge to write a function sortStack that receives a stack of integers into ascending order (with largest integers on top) and returns another stack ...
9
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2answers
2k views

Balanced parentheses using standard C++

Here is a small program for checking if the parentheses are balanced or not. I am new to the standard library, and this is my first program. How can I improve it? Any kind of modifications or ...
4
votes
2answers
66 views

Thread-safe stack in Java with fixed capacity

Implement a multi-threaded stack, with freedom to use existing implementations of stack. On top of being thread-safe, it must block (not busy-wait) a pushing thread when stack is full and a ...
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1answer
55 views

Generic Custom STACK Class for Hanoi Problem in C# [closed]

I have created a custom class (Generic) in C# for the Hanoi problem. and I am not sure I did the correct thing. ...
4
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2answers
106 views

Create a min stack

The task is taken from leetcode Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- Removes ...
4
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1answer
41 views

Directory Stacks with Python

I implemented basic pushd and popd functionality for a Python script. What's a more academic/formal way to implement a directory ...
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2answers
135 views

Leetcode - find if BST is valid or not

Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node'...
8
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3answers
198 views

Stack as a Persistent Data Structure Implementation

After reading some articles about immutability, I found out that there are persistent data structures. In the following, I implemented a stack as a persistent data structure. What I like about the ...
5
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3answers
793 views

Stack Interview Code methods made from class Node and Smart Pointers

Mainly looking for feedback on my use of smart pointers to implement a standard stack. For interview level production code I have also include a namespace and asserts to test my class, let me know if ...
5
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2answers
75 views

Stack template using linked list

I'm working on a stack implementation using a linked list, but I have a strong feeling that I overcomplicated my solution. I would appreciate it if you review this code and give me any suggestions on ...
22
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3answers
5k views

Leetcode: Valid parentheses

https://leetcode.com/problems/valid-parentheses/ Given a string containing just the characters (, ), ...
1
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1answer
265 views

C++ Updated Stack Code

The original question can be seen here: Stack implementation in C++ using linked list Changes (with the help of Martin): Added copy constructor and assignment operator overload Changed return type ...
5
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2answers
132 views

Stack implementation in C++ using linked list

I am learning C++ and I made a simple stack class using a (reversed) linked-list to test my knowledge. Are there any problems with the following code, or any suggestions to improve it? I want to ...
2
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2answers
156 views

Using the stack algorithm for parenthesis matching

I have used Stacks to check for brackets mismatch. (Parentheses matching problem using Stack algorithm) Any suggestions on how to improve the code? I have tried various examples and it works ...
3
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2answers
159 views

Stack implementation in C++ including min(), max() functions in O(1)

This implementation seems to work. I would love to get any suggestions / comments on how this code could be improved. Are there any potential memory management issues? Any additional methods that ...
1
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2answers
45 views

Stack Array implementation of Java

This is my array implementation on stack in Java. It involves push, pop, get and growth when limit of array size is reached. I am a self-taught programmer starting to learn data structures and ...
2
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1answer
219 views

Stack using Linked List in Swift

I made this implementation of a stack in Swift that stores its elements as a linked list. It seems to work perfectly well, but I’m wondering how I can improve it to follow the best practices of the ...
2
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3answers
220 views

Implementing a stack using a linked-list

In my intro CS class we're reviewing data structures. I'm currently working on implementing a stack using a linked list (LIFO) in C. I'd appreciate a review of the implementation as well as of my ...
2
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2answers
104 views

LinkedList Stack Implementation

I'm new to the programming and I want to ask a question about my linkedlist stack implementation if it's correct and if it meets the requirements of the linkedlist stack implementation. If there is ...
3
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0answers
90 views

Generic stack data structure using linked list and smart pointers

I have decided to rewrite what I did here, following the suggestions to use smart pointers. I will rewrite the other data structures as well using smart pointers where appropriate. I just want to see ...
3
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0answers
94 views

All the paths from the root to the leaves

Given a binary tree, return all root-to-leaf paths. Example: -- 1 / \ 2 3 \ 5 Output should be: ["1->2->5", "1->3"] My approach: I walk the branches ...
0
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1answer
209 views

Iteratively determine the diameter of a binary tree

Can the performance of the iterative approach be improved? I find that this approach lags behind many recursive options. no recursive answers, please. Baseline recursive approach: takes 52 steps ...
3
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2answers
73 views

A Stack Implementation In C

I've written a very simple linked list based stack implementation and was wondering if this is the standard way to do it in C. ...
1
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3answers
89 views

Stack implemented with linked list

I have looked at some previous posts and changed my code accordingly. Do you have some suggestions about my current code? Here are my specific questions: What should ...
3
votes
2answers
159 views

Implementing a stack with Java

I am trying to implement a stack with Java: ...
3
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3answers
556 views

Threadsafe Stack

Here is a class which I have written to create a simple Stack data structure which can be shared across multiple threads. It's a simple LIFO which has 2 operations: one to push onto the top of the ...
5
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3answers
609 views

Abstract Data Type: Stack implementation in C++

While trying to get better at C++ I tried my hand at making a stack implementation. This is the result: ...
4
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3answers
664 views

Generic Stack Data Structure Using Linked Lists

I am a mathematician attempting to become proficient with C++. At the moment I am learning about data structures. I am now writing a stack data structure using linked list from scratch. I have tested ...
2
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1answer
86 views

Unit Testing- simple stack class

This is my first real attempt at unit testing. This is an area I'm currently focused on improving. I say this because I would greatly appreciate any and every improvement! Stack code: ...
3
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0answers
423 views

Find redundant braces in an input string

I am solving interview questions from here. Problem : Write a program to validate if the input string has redundant braces Return 0/1 : ...
3
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3answers
1k views

Array-based stack

Description: An array-based Stack class. Since this class is designed using an array the size of the Stack is limited to ...
3
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2answers
83 views

Python 2 Stack and LinkedList implementation

I'm currently implementing data structures and algorithms I studed in my college course. This is my implementation of a singly linked list and a stack. I would appreciate some feedback in terms of the ...
4
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2answers
2k views

Check if brackets are balanced

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6
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1answer
165 views

Multiple stacks implemented via a linked lists on top of single fixed-size array

Problem Statement Originally, the problem is defined in the book as following: Describe how you could use a single array to implement three stacks. — Cracking the Coding Interview (6th edition) ...
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2answers
100 views

List operation while implementing stack

This is a very basic problem of implementing a queue operation using two stacks. Until now there are no issues with the logic but the testing tool report it takes more time than usual. Test case ...
10
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4answers
891 views

Validator for mathematical expression in infix form

This program will validate whether a mathematical expression entered by the user is a valid expression based off whether the expression itself has been entered with the correct scope openers and scope ...
8
votes
1answer
173 views

Compute the height of a tower made of buckets

I need to speed up my algorithm. It is about finding the height of a tower. The tower is built from buckets. Each bucket has height and radius (1 <= height,radius <= 1000). Variable ...
5
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1answer
516 views

Stack implementation with singly linked list

The following is my implementation of a stack using a linked list. ...
4
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1answer
872 views

Stack implementation using a singly linked list

I've implemented a stack using a singly linked list and would like to know if there are any things I could improve on. StackList.h: ...
2
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3answers
546 views

A Stack Template

Why you're here: Today I bring you a simple Stack Machine and a Lot of questions. I am trying to gain a little bit more understanding of pointers, memory management and templates and thought a Stack ...
2
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2answers
330 views

Converting prefix expressions to infix

Here is my new working code. Man, working with strings in C is tedious and annoying. I had built the algorithm in short time, took hours figuring how to implement it properly in C. Tell me if there ...
1
vote
2answers
766 views

Eight Queens Recursive

I am working on a Java textbook chapter on recursion, and I am to implement an Eight Queens solution using recursion. Though I know that I am to post working code in Code Review, I do believe this ...
14
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3answers
1k views

Stack Implementation in C++ with Exceptions

Appreciate your thoughts and feedback... Stack.h ...
0
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2answers
113 views

C++ Stack implementation with linked-list

It's proving difficult to find implementations of a Stack with linked list and Im trying to figure out if my implementation is correct/not missing anything obvious. ...