Stack

Time and Space Complexity of Stack

In this article, we will explore about various operations on Stack Data Structure and the Time and Space Complexity of each operation for various cases like Best case, Average case and Worst case.

Algorithms

Delete middle element of Stack

In this article, we discuss an iterative and recursive approach to delete the middle element of a stack.

Algorithms

Merge Intervals problem

In this article, we will learn how to solve the Merge Overlapping Intervals problem in most efficient and easy to understand method with the help of stack. We do this in linear time O(N).

Algorithms

Implement K stacks in one array

In this article, we have present two approaches to design K stacks in one array. The challenge is to efficiently store the elements to use all available space in the array and maintain the time complexity of stack operations.

Algorithms

Invert / Reverse a Binary Tree [3 methods]

Inverting a binary tree is one of the most common questions asked in the interviews of many companies. In this article, we will see in detail as to how one can understand and tackle this task of inverting a binary tree using recursion, stack and queue.

Algorithms

Arithmetic Expression Evaluation using Stack

We have explained how an Arithmetic Expression (like 2 * 3 + 4) is evaluated using Stack. We have presented the algorithms and time/ space complexity.

Algorithms

Bubble Sort using Two Stacks

We have explored the algorithm to perform Bubble Sorting Algorithm using Two Stacks and sort a given array.

Algorithms

Shortest Unsorted Continuous Subarray

We have solved the problem "Shortest Unsorted Continuous Subarray" and explained the logic behind it and what are the different methods (like Monotonic Stack) we can use to solve it efficiently.

Algorithms

Remove K digits to make smallest number

We will be solving the problem of removing K digits from a given number to form the smallest number possible without changing the order of the original number. We will use the idea of Monotonic Stack

Algorithms

Insert element at bottom of Stack [Explained]

In this article, we have explained how to insert an element at the bottom of Stack using standard stack operations like push and pop. We have covered two approaches: iterative and recursive.

Algorithms

Make String Stable [using Stack]

Given a string with opening and closing braces, our problem is to find the minimum number of operations to make the string stable. This can be solved efficiently using Stack.

Algorithms

132 Pattern Problem [Solved]

In this article, we have explained what is 132 pattern problem and have discussed 3 different approaches to solve it in linear time O(N) where brute force approach takes O(N^3) time.

Algorithms

Different ways to sort a Queue

We will be discussing 4 different ways to sort a queue. This involves sorting a Queue using auxiliary array, O(1) space, using recursion and using a stack.

Algorithms

Implementing two stacks in one array

We will demonstrate how to implement 2 stacks in one array. Both stacks are independent but use the same array. We need to make sure one stack does not interfere with the other stack and support push and pop operation accordingly.

Algorithms

Reverse first K elements of Queue using Stack

To reverse the first K elements of a queue, we can use an auxiliary stack. We push the first k elements in the stack and pop() them out so and add them at the end of the queue.

Algorithms

Reverse a Stack

The objective of this article is to explore various approaches that can be used to reverse the given stack (stack is a linear data structure where insertion and deletion are made at the same end).

Algorithms

C program to check whether brackets are Balanced in an Equation

We have developed a C program to check whether brackets are Balanced in an Equation using the Stack data structure and solving it in O(N) time.

Data Structures

Sort a stack using another stack

In this article, we have explored an algorithm to sort a stack using another stack that is by using stack operations like push and pop only. The time complexity of this approach is O(N^2) and space complexity is O(N).

Data Structures

Dynamic Stack

Dynamic Stack, just like Dynamic Array, is a stack data structure whose the length or capacity (maximum number of elements that can be stored) increases or decreases in real time based on the operations (like insertion or deletion) performed on it.

Software Engineering

Initialize Stack in C++ STL

std::stack is a type of container adapter, specifically designed to operate in a LIFO fashion elements can be inserted or removed from only one end

Algorithms

Converting Postfix to Infix using Stack

We have explored an algorithm to convert a Postfix expression to Infix expression using Stack. This takes linear time O(N)

C++

Stack in C++ STL

Stack in the STL of C++ is a dynamically resizing container. Stack class is an container adapter. Containers or container classes store objects and data. There are in total seven standard "first-class" container classes and three container adaptor classes and only seven header files

Data Structures

Implementing Stack using queues in two ways

A stack is based on the principle of Last-in-First-Out(LIFO). It is commonly used abstract data type with two major operations, namely pop and push. Push() and pop() are carried out in the topmost element, which is the item most recently added to the stack. Push operation adds an element to stack

Data Structures

Stack

Stack serves two principal operations: push, which adds an element to the collection, and pop, which removes the most recently added element that was not yet removed. We have covered functions like top, isFull, isEmpty, peek, pop, push and given an implementation example

Algorithms

Conversion of Infix to Postfix Expression using Stack

To convert Infix expression to Postfix expression, we will use the stack data structure. By scanning the infix expression from left to right,if we get any operand, simply add it to the postfix form, and for the operator and parenthesis, add them in the stack maintaining the precedence of them.