import java.util.NoSuchElementException; import java.util.Iterator; import java.lang.Iterable; public class LinkedList implements Iterable{ class Node{ T value; Node next; Node prev; Node(T value){ this.value=value; this.next=null; this.prev=null; } } class MyIterator implements Iterator{ Node cursor; MyIterator() { cursor=head; } @Override public boolean hasNext() { return cursor!=null; } @Override public T next() { if (cursor==null) throw new NoSuchElementException(); Node next = cursor; cursor = cursor.next; return next.value; } } Node head; Node tail; int size; LinkedList(){ this.head=null; this.tail=null; this.size=0; } public T remove(int pos){ if(this.head==null||pos<0||pos>=this.size) throw new NoSuchElementException(); if(pos==0) return removeFirst(); if(pos==this.size-1) return removeLast(); Node cursor=this.head; while(pos-->0){ if(cursor.next!=null) cursor=cursor.next; else throw new NoSuchElementException(); } Node removed=cursor; cursor.prev.next=cursor.next; cursor.next.prev=cursor.prev; this.size--; return removed.value; } public T removeFirst(){ Node removed=this.head; if(removed==null) throw new NoSuchElementException(); this.head=this.head.next; if(this.head!=null) this.head.prev=null; this.size--; return removed.value; } public T removeLast(){ Node removed=this.tail; if(removed==null) throw new NoSuchElementException(); this.tail=this.tail.prev; if(this.tail!=null) this.tail.next=null; this.size--; return removed.value; } public void add(int pos, T element){ if(pos==0){ addFirst(element); return ; } if(pos==this.size){ addLast(element); return; } if(this.head==null||pos<0) throw new NoSuchElementException(); Node cursor=this.head; Node newNode=new Node(element); while(pos-->0){ if(cursor.next!=null) cursor=cursor.next; else throw new NoSuchElementException(); } newNode.next=cursor; cursor.prev.next=newNode; cursor.prev=newNode; this.size++; } public void add(T element){ addLast(element); } public void addFirst(T element){; Node newNode=new Node(element); if(this.head==null){ this.head=newNode; this.tail=newNode; }else{ this.head.prev=newNode; newNode.next=this.head; this.head=newNode; } this.size++; } public void addLast(T element){ Node newNode=new Node(element); if(this.head==null){ this.head=newNode; this.tail=newNode; }else{ this.tail.next=newNode; newNode.prev=this.tail; this.tail=newNode; } this.size++; } public T get(int pos){ if(this.head==null||pos<0) throw new NoSuchElementException(); Node cursor=this.head; while(pos-->0){ if(cursor.next!=null) cursor=cursor.next; else throw new NoSuchElementException(); } return cursor.value; } public T getFirst(){ if(this.head==null) throw new NoSuchElementException(); return this.head.value; } public T getLast(){ if(this.tail==null) throw new NoSuchElementException(); return this.tail.value; } public void set(int pos, T element){ if(this.head==null||pos<0||pos>this.size-1) throw new NoSuchElementException(); if(pos==0){ this.head.value=element; return; } if(pos==this.size-1){ this.tail.value=element; return; } Node cursor=this.head; while(pos-->0){ if(cursor.next!=null) cursor=cursor.next; else throw new NoSuchElementException(); } cursor.value=element; } public int indexOf(T element){ if(this.head==null) return -1; Node cursor=this.head; int pos=0; do{ if(cursor.value==element) return pos; pos++; if(cursor.next!=null) cursor=cursor.next; else break; }while(true); return -1; } public int lastIndexOf(T element){ if(this.tail==null) return -1; Node cursor=this.tail; int pos=this.size-1; do{ if(cursor.value==element) return pos; pos--; if(cursor.prev!=null) cursor=cursor.prev; else break; }while(true); return -1; } @Override public Iterator iterator(){ return new MyIterator(); } public int size(){ return this.size; } @Override public String toString(){ String str=""; if(this.head!=null){ Node cursor=this.head; while(cursor.next!=null){ str+=cursor.value+", "; cursor=cursor.next; } str+=cursor.value; } return str; } } public class Program{ public static void main(String[] args) { LinkedList l=new LinkedList(); for(int i=0;i<5;i++) l.add(i); l.add(5,5); l.add(6,5); l.remove(5); for(int i=0;i<6;i++) System.out.println(l.get(i)); LinkedListlist=new LinkedList(); list.add("sandals"); list.add("sunglasses"); list.add("shirt"); list.add("shorts"); list.addFirst("shorts"); list.addFirst("umbrella"); list.set(4,"tshirt"); list.addLast("sunscreen lotion"); System.out.println("\n"+list); System.out.println("\nindexOf shorts: "+list.indexOf("shorts")); System.out.println("\nlastIndexOf shorts: "+list.lastIndexOf("shorts")); list.remove(list.lastIndexOf("shorts")); System.out.println("\n"+list); var iter=list.iterator(); System.out.println("\n~~~~WhileIteratorHasNextLoop~~~~"); while(iter.hasNext()) System.out.println(iter.next()); System.out.println("\n~~~~forOfLoop~~~~"); for(String value:list){ System.out.println(value); } } }

LinkedList - Iterable Iterator