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.
358
questions
2
votes
2answers
71 views
Designing a stack such that getMin() is both constant time and constant space
I'm attempting the SpecialStack problem on GeeksforGeeks.
Design a data-structure SpecialStack (using the STL of stack) that
supports all the stack operations like push(), pop(), isEmpty(),
...
0
votes
1answer
82 views
Syntax Checker C++ Data Structure - Stack
Syntax Checker is a very common question of c++ programming using the data structure stack. However, this is the advanced level base on this question I found in a reference book. Here is the question:
...
3
votes
0answers
49 views
Stack Structure in R
I've written a stack implementation in R using S4 Classes. I would like feedback concerning anything with the application because it's my very first program in <...
18
votes
8answers
3k views
Stack data structure in Python 3
I have implemented a stack in Python 3, and it works well. If anything needs to be improved, I would appreciate the criticism.
...
6
votes
1answer
65 views
Doubly Linked List using Stack in c++
Just started learning/relearning data structures for the semester exams. Most of the examples found online are too cluttered or bloated.
For myself, I implemented it from theory I learned.
It works....
1
vote
1answer
128 views
Codility's stonewall 100% solution - different paths such as if,else if,etc, do the same thing
Here is the task description for the codility's stonewall problem. I would like to get a feedback on my code, and I specify at the bottom what the title states. (I had to make the figure by hand, ...
3
votes
1answer
62 views
Codility voracious fish are moving along a river, solution in C#
This is the task's description. My code gets 100% task score. Is it good code yet? (I think I'm getting a lot better, since I started solving this codility's exercises and posting here, but I always ...
1
vote
0answers
79 views
LeetCode: Daily Temperatures C#
https://leetcode.com/problems/daily-temperatures/
Given a list of daily temperatures T, return a list such that, for
each day in the input, tells you how many days you would have to wait
until ...
2
votes
2answers
61 views
Creating a stack class in C++
Create a class called Stack for storing integers. The data members are
an integer array for storing the integers and an integer for storing
the top of stack (<...
5
votes
1answer
64 views
An alternative algorithm for sorting a stack using only one additional stack
From "Cracking the Coding Interview":
Write a program to sort a stack in ascending order (with biggest items on top). You may use at most one additional stack to hold items, but you may not copy ...
6
votes
5answers
126 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 ...
13
votes
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
votes
2answers
84 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
votes
2answers
153 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
76 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
votes
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
votes
3answers
648 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
votes
2answers
3k 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
114 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 ...
-4
votes
1answer
56 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
votes
2answers
206 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
votes
1answer
60 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 ...
1
vote
2answers
161 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
votes
3answers
384 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
votes
3answers
798 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
votes
2answers
80 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 ...
23
votes
3answers
5k views
Leetcode: Valid parentheses
https://leetcode.com/problems/valid-parentheses/
Given a string containing just the characters (, ), ...
1
vote
1answer
282 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
votes
2answers
142 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
votes
2answers
270 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
votes
2answers
163 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
vote
2answers
48 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
votes
1answer
254 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
votes
3answers
274 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
votes
2answers
109 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
votes
0answers
91 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 ...
4
votes
0answers
105 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
votes
1answer
273 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
votes
2answers
76 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
vote
3answers
90 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
162 views
3
votes
3answers
763 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
votes
3answers
841 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
votes
3answers
672 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
votes
1answer
111 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
votes
0answers
473 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
votes
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
votes
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
votes
2answers
2k views
6
votes
1answer
258 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)
...
