/***********
	Nós
************/

public class pOneChildNode{
    protected Object data;
    protected pOneChildNode next;

    public pOneChildNode(){
        next = null;
        data = null;
    }
    public pOneChildNode(Object d,pOneChildNode n){
        data = d;
        next = n;
    }
    public void setNext(pOneChildNode n){
        next = n;
    }
    public void setData(Object d){
        data = d;
    }
    public pOneChildNode getNext(){
        return next;
    }
    public Object getData(){
        return data;
    }
    public String toString(){
        return ""+data;
    }
}

/***************
	LISTAS
****************/

public class pLinkedList{
    protected pOneChildNode head;
    protected int number;

    public pLinkedList(){
        head = null;
        number = 0;
    }
    public boolean isEmpty(){
        return head == null;
    }
    public int size(){
        return number;
    }
    public void insert(Object obj){
        head = new pOneChildNode(obj,head);
        number++;
    }
    public Object remove(){
        if(isEmpty())
            return null;
        pOneChildNode tmp = head;
        head = tmp.getNext();
        number--;
        return tmp.getData();
    }
    public void insertEnd(Object obj){
        if(isEmpty())
            insert(obj);
        else{
            pOneChildNode t = head;
            while(t.getNext() != null)
                t=t.getNext();
            pOneChildNode tmp =
                new pOneChildNode(obj,t.getNext());
            t.setNext(tmp);
            number++;
        }
    }
    public Object removeEnd(){
        if(isEmpty())
            return null;
        if(head.getNext() == null)
            return remove();
        pOneChildNode t = head;
        while(t.getNext().getNext() != null)
            t = t.getNext();
        Object obj = t.getNext().getData();
        t.setNext(t.getNext().getNext());
        number--;
        return obj;
    }
    public Object peek(int n){
        pOneChildNode t = head;
        for(int i = 0;i<n && t != null;i++)
            t = t.getNext();
        return t.getData();
    }
}

/**************
	TESTE
***************/

class pLinkedListTest{
    public static void main(String[] args){
        pLinkedList l = new pLinkedList();
        Integer j = null;
        int i;
        System.out.println("Iniciando...");
        for(i=0;i<5;i++){
            j = new Integer((int)(Math.random() * 100));
            l.insert(j);
            System.out.println("insert: " + j);
        }
        for(;i<10;i++){
            j = new Integer((int)(Math.random() * 100));
            l.insertEnd(j);
            System.out.println("insertEnd: " + j);
        }
        for(i=0;i<l.size();i++)
            System.out.println("peek "+i+": "+l.peek(i));
        for(i=0;i<5;i++)
            System.out.println("remove: " + ((Integer)l.remove()));
        while(!l.isEmpty())
            System.out.println("removeEnd: " + ((Integer)l.removeEnd()));
        System.out.println("Fim!!!");
    }
}