65 lines
1.5 KiB
Java
65 lines
1.5 KiB
Java
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class Node<T> {
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T data;
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Node<T> next;
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Node(T data) {
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this.data = data;
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this.next = null;
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}
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}
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public class SinglyLinkedList<T> {
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Node<T> head;
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SinglyLinkedList() {
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this.head = null;
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}
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void insertAtHead(T data) {
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Node<T> newNode = new Node<T>(data);
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if(this.head == null) {
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this.head = newNode;
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} else {
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newNode.next = this.head;
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this.head = newNode;
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}
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}
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T removeAtHead() {
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// check for underflow
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if(this.head == null) {
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System.out.println("Underflow");
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System.exit(1);
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}
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// store data for return
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T data = this.head.data;
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this.head = this.head.next;
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return data;
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}
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void printList() {
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// if head is null then list is empty
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if(this.head == null) {
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System.out.println("List is Empty");
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} else {
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// take itr same as head reference and loop through it until it became null
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Node<T> itr = this.head;
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while(itr != null) {
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System.out.print(itr.data + " ");
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itr = itr.next;
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}
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System.out.println("");
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}
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}
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// Test Code
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public static void main(String... args) {
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SinglyLinkedList<String> l = new SinglyLinkedList<String>();
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l.insertAtHead("abc");
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l.insertAtHead("pqr");
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l.insertAtHead("xyz");
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l.removeAtHead();
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l.printList();
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}
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}
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