NthNodeFromEnd.java

package datastructure.list.program;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

/**
 * Given a Linked List and a number n, write a function that returns the value
 * at the n’th node from end of the Linked List.
 * 
 * @author skedia
 *
 */
public class NthNodeFromEnd {

    static int i = 0;
    static int data = 0;

    public static void main(String[] args) {
	// list to perform on
	List<Integer> intList = getLinkedList();
	// index from end
	int n = 5;
	Iterator<Integer> intListIterator = intList.iterator();
	getNthNodeFromEnd(intListIterator, n);
	System.out.println(data);
    }

    /**
     * Returns the data of nth node from end of a list
     * 
     * @param intListIterator
     * @param n
     */
    private static void getNthNodeFromEnd(Iterator<Integer> intListIterator, int n) {
	// if it is the last node of List make index = 1 and return
	if (!intListIterator.hasNext()) {
	    i = 1;
	    return;
	}
	// assign the node value to a temp variable
	int temp = intListIterator.next();
	// recurse the list to the end
	getNthNodeFromEnd(intListIterator, n);
	// if i equals n then assign node value in temp variable to data
	if (i == n)
	    data = temp;
	// increment i and return
	i++;
	return;
    }

    /**
     * Return a pre-constructed list to perform on.
     * 
     * @return List
     */
    private static List<Integer> getLinkedList() {
	List<Integer> intList = new LinkedList<Integer>();
	intList.add(4);
	intList.add(8);
	intList.add(2);
	intList.add(9);
	intList.add(5);
	intList.add(1);
	intList.add(12);
	intList.add(10);
	intList.add(3);
	intList.add(32);
	intList.add(11);
	return intList;
    }

}