Question

I have a question regarding LinkedList that I’m using to implement a queue. How to move to the tail all elements that stay before the defined element? Let’s say I need to move to the tail all elements that stay before the 3rd element (see the below example). It means that the numbers 1 and 2 should be moved to the tail in order to get: 3->4->1->2.

Is it possible to do something similar to list1.moveToTheTail(startElem,endElem); where startElem and endElem indicate bounds of elements to be moved to the tail?

import java.util.LinkedList;

public class Test {
    public static void main(String[] args) {
        LinkedList<Integer> list1 = new LinkedList<Integer>();
        list1.addLast(1);
        list1.addLast(2);
        list1.addLast(3);
        list1.addLast(4);
        list1.
        System.out.println(list1);
    }
}

Answer 1

no there is no such function .. it’s a pity because the operation move from front to tail is only a change of the “pointer” to the first element.

But you want a function to move also from the middle of the list … here we go:

public static void moveToTail(LinkedList<?> list,int startElement, int endElement) {
    if (startElement <0 )
        return ;
    if (endElement < startElement)
        return;
    if (endElement >= list.size())
        return;
    for(int i = startElement ; i < endElement ; ++i) {
         //yeah it has to be startElement and not i
         list.addLast(list.remove(startElement));
    }
}