Question
In an ancient land, the beautiful princess Eve had many suitors. She decided on the following procedure to determine which suitor she would marry. First, all of the suitors would be lined up one after the other and assigned numbers. The first suitor would be number 1, the second number 2, and so on up to the last suitor, number n . Starting at the suitor in the first position, she would then count three suitors down the line (because of the three letters in her name), and the third suitor would be eliminated from winning her hand and removed from the line. Eve would then continue, counting three more suitors, and eliminate every third suitor. When she reached the end of the line, she would continue counting from the beginning.
For example, if there were six suitors, the elimination process would proceed as follows:
123456 Initial list of suitors; start counting from 1.
12456 Suitor 3 eliminated; continue counting from 4.
1245 Suitor 6 eliminated; continue counting from 1.
125 Suitor 4 eliminated; continue counting from 5.
15 Suitor 2 eliminated; continue counting from 5.
1 Suitor 5 eliminated; 1 is the lucky winner.
Write a program that creates a circular linked list of nodes to determine which position you should stand in to marry the princess if there are n suitors. Your program should simulate the elimination process by deleting the node that corresponds to the suitor that is eliminated for each step in the process.
Answer
public class CircularLinkedListTest
{
private Node head;
private int size;
private class Node
{
private int num;
private Node next;
public Node(int n)
{
num = n;
next = null;
}
public int getNum()
{
return num;
}
public void setNext(Node n)
{
this.next = n;
}
public Node getNext()
{
return next;
}
}
public CircularLinkedListTest ()
{
head = null;
int numNodes = 0;
}
public void add(int num)
{
int numNodes = 0;
if(head == null)
{
head = new Node(num);
head.setNext(head);
numNodes++;
}
else
{
Node temp = head;
while(temp.getNext() != head)
temp = temp.getNext();
temp.setNext(new Node(num));
temp.getNext().setNext(head);
numNodes++;
}
}
public int size()
{
int numNodes = 0;
return numNodes;
}
public int get(int index)
{
Node t = head;
for(int i = 0; i < index; i++)
t= t.getNext();
return t.getNum();
}
public int remove(int index)
{
if(index < 0 || index >= size)
{
System.out.println("Error, index out of Qbounds.");
System.exit(0);
}
Node temp = head;
if(index == 0)
{
while(temp.getNext() != head)
temp = temp.getNext();
int value = head.getNum();
if(size > 1)
{
head = head.getNext();
temp.setNext(head);
}
else
head = null;
size--;
return value;
}
else
{
for(int i = 0; i < index - 1; i++)
temp = temp.getNext();
int answer = temp.getNext().getNum();
temp.setNext(temp.getNext().getNext());
size--;
return answer;
}
}
public static void main(String args[])
{
CircularLinkedListTest suitors = new CircularLinkedListTest ();
for(int i = 1; i <= 6; i++)
suitors.add(i);
int currentIndex = 0;
while(suitors.size() != 1)
{
for(int i = 1; i <= 2; i++)
{
currentIndex++;
if(currentIndex == suitors.size())
currentIndex = 0;
}
suitors.remove(currentIndex);
if(currentIndex == suitors.size())
currentIndex = 0;
for(int i = 0; i < suitors.size(); i++)
System.out.print(suitors.get(i) + " ");
System.out.println();
}
}
}
OUTPUT:
1 2 4 5 6
1 2 4 5
1 2 5
1 5
1