链表的反转

链表反转

public class ListReverse {
    static Node node1=new Node();
    static {
        node1.data = 1;
        Node node2 = new Node();
        node2.data = 2;
        Node node3 = new Node();
        node3.data = 3;
        Node node4 = new Node();
        node4.data = 4;
        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
    }

    public Node reverse(Node node1) {
        Node pre = null;
        Node next = null;
        Node cur = node1;
        Node headNode = null;
        while (cur != null) {
            next = cur.next;
            if (next==null) {
                headNode=cur;
            }
            cur.next=pre;
            pre=cur;
            cur=next;
        }
        return headNode;
    }

    static class Node {
        int data;
        Node next;
    }

    public static void main(String[] args) {
        ListReverse listReverse=new ListReverse();
        System.out.println("----------"+node1.data);
       Node node= listReverse.reverse(node1);
        System.out.println("----------"+node.data);
    }
}

 

public class ListReverse {
    public Node reverse(Node node1) {
        Node pre = null;
        Node next = null;
        Node cur = node1;
        Node headNode = null;
        while (cur != null) {
            next = cur.next;
            if (next==null) {
                headNode=cur;
            }
            cur.next=pre;
            pre=cur;
            cur=next;
        }
        return headNode;
    }
}