剑指Offer-16

来源：互联网发布：网络b类违规是什么意思编辑：程序博客网时间：2024/06/05 23:41

题目：

反转链表，实现一个函数，输入一个链表的头节点，反转该链表，输出反转后链表的头节点。

实现

//coding = javapublic class Solution16 {    public Node reverseList(Node head){        if(head==null){            return null;        }        if(head.next==null){            return head;        }        Node reverse_head = null;        Node cur_node = head;        Node pre_node = null;        Node next_node;        while (cur_node!=null){            next_node = cur_node.next;            if(next_node == null){                reverse_head = cur_node;            }            cur_node.next = pre_node;            pre_node = cur_node;            cur_node = next_node;        }        return reverse_head;    }    public static Node reverseList2(Node head){        if(head == null){            return null;        }        if(head.next ==null){            return head;        }        Stack<Node> temp = new Stack<>();        while (head!=null){            temp.add(head);            head=head.next;        }        Node reverse_node = temp.pop();        Node cur_node = reverse_node;        while (!temp.empty()){           cur_node.next=temp.pop();           cur_node=cur_node.next;        }        cur_node.next=null;        return reverse_node;    }    public static void main(String[] args){        Node head = new Node(2);        head.next = new Node(3);        head.next.next = new Node(4);        head.next.next.next = new Node(5);        Solution16 s16 = new Solution16();        Node re_head = s16.reverseList(head);        while (re_head!=null){            System.out.print(re_head.value);            re_head = re_head.next;        }    }}

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