77 lines
1.9 KiB
Java
77 lines
1.9 KiB
Java
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class DoublyLinkedList {
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class Node{
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int item;
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Node previous;
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Node next;
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public Node(int item) {
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this.item = item;
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}
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}
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Node head, tail = null;
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public void addNode(int item) {
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Node newNode = new Node(item);
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//if list is empty, head and tail points to newNode
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if(head == null) {
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head = tail = newNode;
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//head's previous will be null
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head.previous = null;
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//tail's next will be null
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tail.next = null;
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}
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else {
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//add newNode to the end of list. tail->next set to newNode
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tail.next = newNode;
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//newNode->previous set to tail
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newNode.previous = tail;
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//newNode becomes new tail
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tail = newNode;
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//tail's next point to null
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tail.next = null;
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}
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}
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public void printNodes() {
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Node current = head;
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if(head == null) {
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System.out.println("Doubly linked list is empty");
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return;
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}
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System.out.println("The doubly linked list is: ");
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System.out.print("[ ");
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while(current != null) {
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System.out.print(current.item + " ");
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//go to next
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current = current.next;
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}
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System.out.print("]");
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}
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}
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public class doubly {
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public static void main(String [] args){
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DoublyLinkedList dl_List = new DoublyLinkedList();
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dl_List.addNode(5);
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dl_List.addNode(7);
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dl_List.addNode(1);
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dl_List.addNode(17);
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dl_List.addNode(27);
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dl_List.printNodes();
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//this will print :
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/*
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The doubly linked list is:
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[ 5 7 1 17 27 ]
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*/
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}
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}
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/*
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to run the file:
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javac doubly.java
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java doubly
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*/
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