Data Structures & Algorithms Tutorials

The Hash table data structure stores elements in key-value pairs where Key– unique integer that is used for indexing the values Value – data that are associated with keys. The key is sent to a hash function that performs arithmetic operations on it. The result (commonly called the hash value or…

A graph data structure is a collection of nodes that have data and are connected to other nodes. Let’s try to understand this through an example. On facebook, everything is a node. That includes User, Photo, Album, Event, Group, Page, Comment, Story, Video, Link, Note…anything that has data is a…

Tree is a data structure similar to a linked list but instead of each node pointing simply to the next node in a linear fashion, each node points to a number of nodes. Tree is an example of non- linear data structures. A tree structure is a way of representing the hierarchical nature of a […]

Heap is a tree-based data structure in which all the nodes of the tree are in a specific order. Heap is a complete binary tree-based data structure. Heaps have specific ordering properties. The ordering can be one of two types: Max-Heap: The value of a node must be greater than or equal to the…

Priority queue is a data structure that extends the queue data structure with a priority dimension. Queue is a list of elements taken in the same order as they arrived. For instance, a line of people waiting to pay at the Supermarket behaves like a queue: first-in, first-served, or FIFO (first in,…

Queue is an ordered list in which insertions are done at one end (back) and deletions are done at other end (front). The first element to be inserted is the first one to be deleted. Hence, it is called First in First out (FIFO) or Last in Last out (LILO) list. In general, a queue […]

ArrayList is a resizable array or dynamic array implementation in java. ArrayList grows dynamically and ensures that there is always a space to add elements. The backing data structure of ArrayList is an array of Object class. ArrayList class in Java has 3 constructors. It has its own version of…

What is RAM? Computer random access memory (RAM) is one of the most important components in determining your system’s performance. RAM gives applications a place to store and access data on a short-term basis. It stores the information your computer is actively using so that it can be accessed…

Array is a data structure that holds a fixed number of values (data points) of the same data type. Each item, or value, is called an element. When we initialize an array, we get to choose what type of data(data type) it can hold and how many elements(length) it can hold. Each position in the […]

A greedy algorithm always makes the best choice at the moment. This means that it makes a locally-optimal choice in the hope that this choice will lead to a globally-optimal solution. Greedy algorithms work in stages. In each stage, a decision is made that is good at that point, without bothering…

Dynamic programming is similar to Divide and Conquer in in that a problem is broken down into smaller sub-problems. But unlike, Divide and Conquer, these sub-problems are not solved independently. Rather, results of these smaller sub-problems are stored and used for similar or overlapping…

Recursion is the technique of making a function call to itself. This technique provides a way to break complicated problems down into simple problems which are easier to solve. Recursion Structure validation of input base case where it stops calling itself and returns a value recursive case,…

Binary Search is a search algorithm that finds the position of a target value within a sorted array. Binary search compares the target value to the middle element of the array. It works only on a sorted set of elements. To use binary search on a collection, the collection must first be sorted. When…

QuickSort is a Divide and Conquer algorithm. It picks an element as pivot and partitions the given array around the picked pivot. There are many different versions of quickSort that pick pivot in different ways. Always pick first element as pivot. Always pick last element as pivot (implemented…

A trie (also known as a digital tree) and sometimes even radix tree or prefix tree (as they can be searched by prefixes), is an ordered tree structure, which takes advantage of the keys that it stores – usually strings. A node’s position in the tree defines the key with which that node is…

Stack is a simple data structure that allows adding and removing elements in a particular order. Every time an element is added, it goes on the top of the stack and the only element that can be removed is the element that is at the top of the stack, just like a pile of objects. A […]

Linked List is a very commonly used linear data structure which consists of group of nodes in a sequence. Each node holds its own data and the address of the next node hence forming a chain like structure. Linked Lists are used to create trees and graphs. Advantages of Linked List Linkedlist is…

Divide and Conquer is a very popular algorithm that many people use to solve problems. With Divide and Conquer, a problem in hand, is divided into smaller sub-problems and then each problem is solved independently. When we keep on dividing the subproblems into even smaller sub-problems, we may…

The Omega notation represents the lower bound of the running time of an algorithm. It provides the best case complexity of an algorithm. So if we represent a complexity of an algorithm in Omega notation, it means that the algorithm cannot be completed in less time than this, it would at least take…

Big O is about how long an algorithm takes to run from start to end and how well it scales as the size of the input or dataset increases. Big O is mostly measured based on the worst-case scenario even though some algorithms might finish earlier than others. Here is another graph for more clarity.…

Data Structures A data structure is exactly what it sounds like — a structure that holds data. Unlike variables, which only hold a single point of data, data structures collect one or more points of data of the same type. Although a data structure can hold many points of data, a data structure,…