链表的反转算法

说到链表的反转，当初第一次接触这个概念的时候，首先想到的办法就是，首先对链表做一个遍历，强行给每个节点记录一个顺序，然后再根据顺序重新构建列表，这种办法虽然可以实现，但是效率不高（主要是取决重新排序生成列表的排序算法复杂度），下面这个办法的算法复杂度仅仅为O（N），附代码   // Java program for reversing the linked list    class LinkedList {        static Node head;        static class Node {            int data;         Node next;            Node(int d) {             data = d;             next = null;         }     }        /* Function to reverse the linked list */     Node reverse(Node node) {         Node prev = null;         Node current = node;         Node next = null;         while (current != null) {             next = current.next;             current.next = prev;             prev = current;             current = next;         }         node = prev;         return node;     }        // prints content of double linked list     void printList(Node node) {         while (node != null) {             System.out.print(node.data + " ");             node = node.next;         }     }        public static void main(String[] args) {         LinkedList list = new LinkedList();         list.head = new Node(85);         list.head.next = new Node(15);         list.head.next.next = new Node(4);         list.head.next.next.next = new Node(20);                    System.out.println("Given Linked list");         list.printList(head);         head = list.reverse(head);         System.out.println("");         System.out.println("Reversed linked list ");         list.printList(head);     } }