21. 合并两个有序链表

素颜马尾好姑娘i 2022-09-08 00:19 191阅读 0赞

[https://leetcode-cn.com/problems/merge-two-sorted-lists/][https_leetcode-cn.com_problems_merge-two-sorted-lists]

难度简单1866

将两个升序链表合并为一个新的 **升序** 链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。

**示例 1：**

![c8c4179fe3b26bb737eb49cfc0105f4e.png][]

输入：l1 = [1,2,4], l2 = [1,3,4]
    输出：[1,1,2,3,4,4]

**示例 2：**

输入：l1 = [], l2 = []
    输出：[]

**示例 3：**

输入：l1 = [], l2 = [0]
    输出：[0]

**提示：**

*  两个链表的节点数目范围是 `[0, 50]`
 *  `-100 <= Node.val <= 100`
 *  `l1` 和 `l2` 均按 **非递减顺序** 排列

通过次数672,342提交次数1,009,156

/**
     * Definition for singly-linked list.
     * public class ListNode {
     *     int val;
     *     ListNode next;
     *     ListNode() {}
     *     ListNode(int val) { this.val = val; }
     *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
     * }
     */
    class Solution {
        public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
            ListNode head = new ListNode();
            ListNode node = head;
            while(l1!=null && l2!=null)
            {
                if(l1.val <= l2.val)
                {
                    node.next = l1;
                    l1 = l1.next;
                }
                else 
                {
                    node.next = l2;
                    l2 = l2.next;
                }
                node = node.next;
            }
            while(l1!=null)
            {
                node.next = l1;
                l1 = l1.next;
                node = node.next;
            }
            while(l2!=null)
            {
                node.next = l2;
                l2 = l2.next; 
                node = node.next; 
            }
            return head.next;
        }
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBA5Yqq5Yqb5a2m5Lmg55qE5qKF5a2Q_size_18_color_FFFFFF_t_70_g_se_x_16][]

[https_leetcode-cn.com_problems_merge-two-sorted-lists]: https://leetcode-cn.com/problems/merge-two-sorted-lists/
[c8c4179fe3b26bb737eb49cfc0105f4e.png]: /images/20220829/23f04d885dfc437fa2daf0dad2abc251.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_Q1NETiBA5Yqq5Yqb5a2m5Lmg55qE5qKF5a2Q_size_18_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/6984b4f1951047939c622d2b9e152a43.png