Every thing U can do with a Link-List + Programming_it_in_JaVa

Linked List
A linked list is a sequence of data structures, which are connected together via links.
Linked List is a sequence of links which contains items. Each link contains a connection to another link. Linked list is the second most-used data structure after array. 
Following are the important terms to understand the concept of Linked List:
  • Link − Each link of a linked list can store a data called an element.
  • Next − Each link of a linked list contains a link to the next link called Next.
  • LinkedList − A Linked List contains the connection link to the first link called First.
Linked list can be visualized as a chain of nodes, where every node points to the next node:
As per the above illustration, following are the important points to be considered.
  • Linked List contains a link element called first.
  • Each link carries a data field(s) and a link field called next.
  • Each link is linked with its next link using its next link.
  • Last link carries a link as null to mark the end of the list.
Basic Operations:
Following are the basic operations supported by a list.
  • Insertion − Adds an element at the beginning of the list.
  • Deletion − Deletes an element at the beginning of the list.
  • Display − Displays the complete list.
  • Search − Searches an element using the given key.
  • Delete − Deletes an element using the given key.

Insertion Operation:

Adding a new node in linked list is a more than one step activity.First, create a node using the same structure and find the location where it has to be inserted.
Insertion operation
Imagine that we are inserting a node B (NewNode), between A (LeftNode) and C (RightNode). Then point B.next to C −
NewNode.next −> RightNode;
It should look like this −
Insertion operation
Now, the next node at the left should point to the new node.
LeftNode.next −> NewNode;
Insertion operation
This will put the new node in the middle of the two. The new list should look like this −
Insertion operation
Similar steps should be taken if the node is being inserted at the beginning of the list. While inserting it at the end, the second last node of the list should point to the new node and the new node will point to NULL.

Deletion Operation

Deletion is also a more than one step process. First, locate the target node to be removed.
Deletion Operation
The left (previous) node of the target node now should point to the next node of the target node −
LeftNode.next −> TargetNode.next;
This will remove the link that was pointing to the target node. Now, using the following code, we will remove what the target node is pointing at.
TargetNode.next −> NULL;
We need to use the deleted node. We can keep that in memory otherwise we can simply deallocate memory and wipe off the target node completely.
Deletion Operation

Reverse Operation:

This operation is a thorough one. We need to make the last node to be pointed by the head node and reverse the whole linked list.
Reverse Operation:

First, we traverse to the end of the list. It should be pointing to NULL. Now, we shall make it point to its previous node −
Reverse Operation:
We have to make sure that the last node is not the lost node. So we’ll have some temp node, which looks like the head node pointing to the last node. Now, we shall make all left side nodes point to their previous nodes one by one.
Reverse Operation:
Except the node (first node) pointed by the head node, all nodes should point to their predecessor, making them their new successor. The first node will point to NULL.
Reverse Operation:
We’ll make the head node point to the new first node by using the temp node.
Reverse Operation:
The linked list is now reversed.

Java LinkedList class

Java LinkedList class uses doubly linked list to store the elements. It provides a linked-list data structure. It inherits the AbstractList class and implements List and Deque interfaces.

Doubly LinkedList:A Doubly Linked List (DLL) contains an extra pointer, typically called previous pointer, together with next pointer and data which are there in singly linked list.

Doubly LinkedList
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The important points about Java LinkedList are:
  • Java LinkedList class can contain duplicate elements.
  • Java LinkedList class maintains insertion order.
  • Java LinkedList class is non synchronized.
  • In Java LinkedList class, manipulation is fast because no shifting needs to be occurred.
  • Java LinkedList class can be used as list, stack or queue.

LinkedList Class Representation:

  1. public class LinkedList extends AbstractSequentialList
  2. implements List  

Constructors of Java LinkedList:

Constructor Description
LinkedList() It is used to construct an empty list.
LinkedList(Collection c) It is used to construct a list containing the elements of the specified collection, in the order they are returned by the collection’s iterator.

Methods of Java LinkedList:

Method Description
void add(int index, Object element) It is used to insert the specified element at the specified position index in a list.
void addFirst(Object o) It is used to insert the given element at the beginning of a list.
void addLast(Object o) It is used to append the given element to the end of a list.
int size() It is used to return the number of elements in a list
boolean add(Object o) It is used to append the specified element to the end of a list.
boolean contains(Object o) It is used to return true if the list contains a specified element.
boolean remove(Object o) It is used to remove the first occurence of the specified element in a list.
Object getFirst() It is used to return the first element in a list.
Object getLast() It is used to return the last element in a list.
int indexOf(Object o) It is used to return the index in a list of the first occurrence of the specified element, or -1 if the list does not contain any element.
int lastIndexOf(Object o) It is used to return the index in a list of the last occurrence of the specified element, or -1 if the list does not contain any element.

Let’s now see an example of LinkedList in java:
import java.util.*;
public class SuvenConsultants{
public static void main(String args[]) {

/* Linked List Declaration */
LinkedList<String> linkedlist = new LinkedList<String>();

/*add(String Element) is used for adding
* the elements to the linked list*/

linkedlist
.add("Android");
linkedlist
.add("Web Technology");


/*Display Linked List Content*/
System.out.println("Linked List Content: " +linkedlist);

/*Add First and Last Element*/
linkedlist
.addFirst("Database");
linkedlist
.addLast("Java");
System.out.println("LinkedList Content after addition: " +linkedlist);

/*This is how to get and set Values*/
Object firstvar = linkedlist.get(0);
System.out.println("First element: " +firstvar);
linkedlist
.set(0, "Data Analytics");
Object firstvar2 = linkedlist.get(0);
System.out.println("First element after update by set method: " +firstvar2);

/*Remove first and last element*/
linkedlist
.removeFirst();
linkedlist
.removeLast();
System.out.println("LinkedList after deletion of first and last element: " +linkedlist);

/* Add to a Position and remove from a position*/
linkedlist
.add(0, "Python");
linkedlist
.remove(2);
System.out.println("Final Content: " +linkedlist);
}
}
Output:
Linked List Content: [Android, Web Technologies]
LinkedList Content after addition: [Database,Android, Web Technologies,Java]
First element: Database
First element after update by set method: Data Analytics
LinkedList after deletion of first and last element: [Android, Web Technologies]
Final Content: [Python, Android]

Advantages of Linked Lists

  • They are a dynamic in nature which allocates the memory when required.
  • Linked List can grow and shrink during run time.
  • Insertion and deletion operations can be easily implemented.
  • Stacks and queues can be easily executed

Disadvantages of Linked List

  • The memory is wasted as pointers require extra memory for storage.
  • No element can be accessed randomly; it has to access each node sequentially.
  • Reverse Traversing is difficult in linked list.

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Oracle Joins the White House in Global Campaign to Empower Girls and Women

Oracle Education Foundation
The Oracle Education Foundation is a nonprofit organization funded by Oracle Corporation. Its mission is to “inspire students globally to think, connect, create and share — using technology to help them dissolve boundaries, fulfill their potential, and create a better society.”
Oracle teamed up with the White House back in April to donate money to support the Obama administration’s Computer Science for All initiative. The goal is to empower and engage student through various computer science programs in over 1,100 US institutions. They hope the money and attention will draw young people around the world into learning about science, technology, engineering and math, or STEM. The company committed $200 million to the cause.

On the heels of Oracle’s $200 million commitment to support Computer Science (CS) Education for All,the White House announced Oracle’s additional $3 million investment to immerse girls worldwide in science, technology, engineering and math (STEM). The company’s commitment of direct and in-kind funding supports “Let Girls Learn,” a U.S. government initiative aimed at helping adolescent girls around the world go to school and stay in school.

We want more girls focused on building upon science and math fundamentals and we want more women choosing the technical disciplines because they are both prepared to do so and because they believe it will advance their career opportunities,” Oracle’s (female) CEO, Safra Catz, said in a statement.

OWL

Oracle will offer more than 65 educational events and reach over 55,000 young girls globally through a powerful nexus of its corporate social responsibility programs spanning Oracle Academy, Oracle Education Foundation, Oracle Giving and Volunteers, (OWL), and Oracle Diversity and Inclusion. Events will include summer computing camps, codefests, workshops and conferences designed to encourage and inspire adolescent girls to become original thinkers, creative designers and enterprising trailblazers.

The money will help to fund programs to send 55,000 young girls around the world to various summer computing camps, codefests, workshops and conferences. Additionally, Oracle plans to expand its CS efforts in Egypt with an additional investment of nearly $1 million in educational resources and services over the next four years. The commitment is part of a new collaboration between the Ministry of Education in Egypt, the United States Agency for International Development (USAID) and Oracle Academy, Oracle’s philanthropic educational program that impacts more than 2.6 million students in 106 countries. The partnership will support computing education in nine newly-created STEM schools throughout the country, including one boarding school exclusively for girls which will accept up the top 10 percent of girls across the governorates, reaching 150 girls each year and providing three years of paid education for each girl.
With the donation, Oracle joins several other technology companies which are participating in the White House’s computer science program. Both Google (GOOG, +0.89%) and Salesforce (CRM, +0.17%) (as well as the Cartoon Network) said they would donate in aggregate over $60 million to the program when it was first announced.
As part of the company’s global campaign to support girls and women in technology, Oracle will drive several notable projects:
  • Oracle Academy will team with Arizona State University and others under the USAID Build-IT project to help women in Vietnam develop into IT leaders.
  • Oracle Education Foundation and Oracle Volunteers will team to teach girls coding, electrical engineering and project management through girls-only workshops for Design Tech High School (d.tech), an innovative, free California public high school. Oracle is building d.tech’s new facility at its headquarters in Redwood Shores, Calif., making d.tech the world’s first public high school on a technology campus.
  • Oracle Giving and Oracle Academy will award grants and sponsorships globally to nonprofit organizations striving to increase girls’ access to educational opportunities and encourage them to pursue degrees in computer science and STEM fields.
  • Oracle Giving will continue its support for MentorNet, which engages STEM professionals in the virtual mentoring of undergraduates, 66% of whom are women.
Oracle Academy, a computer science educational program, and Burning Glass Technology, an analytics company, recently did research and found that programming jobs grow 50 percent faster than the market average. As technology is increasingly present in people’s personal and professional lives, there is a need for computer science learning.

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