---
title: 【LeetCode】0021. Merge Two Sorted Lists
date: 2019-06-17
is_modified: false
disqus: cynthiahackmd
categories:
- "面試刷題"
tags:
- "LeetCode"
---

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<br>

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

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<br>

**Example 1:**

Input: 1->2->4, 1->3->4
Output: 1->1->2->3->4->4

<br>

**Related Topics:** `Linked List`

## 解題邏輯與實作
因為題目給的是兩個有序的鏈結串列，所以這題只須兩個指針分別指向給定的陣列，將節點值較小的添加到新的鏈結串列，添加完後將指標移往下一個節點，直到兩鏈結串列的節點都被添加到新的鏈結串列為止。

class Solution:
   def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
      dummy = ListNode(-1)
      head = dummy

      while l1 and l2:
         if l1.val < l2.val:
            head.next = l1
            l1 = l1.next      
         else:
            head.next = l2
            l2 = l2.next
            
         head = head.next

      head.next = l1 if l1 else l2
      return dummy.next

## 其他連結
1. [【LeetCode】0000. 解題目錄](/x62skqpKStKMxRepJ6iqQQ)

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