/**
 * 反轉連結串列
 * @author MA
 *
 */
public class Main {
   static class Node{
	   int val;
	   Node next;
	   public Node(int val){
		   this.val = val;
	   }
   }
   
   public static Node reverseList(Node head){
	   if(head.next == null){
		   return null;
	   }
	   Node node = head;
	   Node frontnode = null;
	   Node rhead = null;
	   Node next = null;
	   
	   while(node != null){
		   next = node.next;
		   
		   if(node.next == null){
			   rhead = node;
		   }
		   
		   node.next = frontnode;
		   frontnode = node;
		   node = node.next;
	   }
	   return rhead;
   }
}