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:
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]
来源:力扣(LeetCode)
链接:https://leetcode-cn.com/problems/merge-two-sorted-lists
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一解
使用双指针:
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:
def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
res = ListNode(None)
tmp = res
while l1 and l2:
if l1.val > l2.val:
tmp.next = l2
l2 = l2.next
else:
tmp.next = l1
l1 = l1.next
tmp = tmp.next
tmp.next = l1 if l1 else l2
return res.next