---
title: "21. Merge Two Sorted Lists"
created: 2025-12-17
---
# 21. Merge Two Sorted Lists

## 题目 [**21. Merge Two Sorted Lists**](https://leetcode.com/problems/merge-two-sorted-lists/)

![[image-3adc6189.png]]

## 思路分析

类似于归并排序

## 代码实现

```java
/**
 * 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 list1, ListNode list2) {
        ListNode head = new ListNode(-1);
        ListNode tail = head;

        while(list1!=null && list2!=null){
            if(list1.val <= list2.val){
                tail.next = list1;
                list1=list1.next;
            }else{
                tail.next = list2;
                list2=list2.next;
            }
            tail=tail.next;
        }
        if(list1!=null){
            tail.next=list1;
        }else{
            tail.next=list2;
        }
        return head.next;
    }
}
```

## 同类题型

## 视频讲解