LeetCode206

给你单链表的头节点 head ，请你反转链表，并返回反转后的链表。

public static ListNode reverseList(ListNode head) {
    // 跳出循环标记，当没有下一节点的时候下次跳出循环
    boolean pass = false;
    // 当前节点
    ListNode curr = null;
    while (!pass) {
        ListNode next = head.next;
        if (next == null) {
            pass = true;
        }
        if (curr == null) {
            // 初始化第一个尾节点
            curr = new ListNode(head.val);
        } else {
            curr = new ListNode(head.val, curr);
        }
        head = head.next;
    }

    return curr;
}

public class ListNode {
    public int val;
    public ListNode next;

    public ListNode() {
    }

    public ListNode(int val) {
        this.val = val;
    }

    public ListNode(int val, ListNode next) {
        this.val = val;
        this.next = next;
    }
}