[LeetCode]21 合并两个有序链表

题目描述

将两个有序链表合并为一个新的有序链表并返回。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:

输入：1->2->4, 1->3->4
输出：1->1->2->3->4->4

代码

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# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def mergeTwoLists(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        head = ListNode(0)
        tprev = head
        t1 = l1
        t2 = l2
        while t1 is not None and t2 is not None:
            if t1.val <= t2.val:
                tprev.next = t1
                t1 = t1.next
            else:
                tprev.next = t2
                t2 = t2.next
            tprev = tprev.next
        if t1 is None:
            tprev.next = t2
        if t2 is None:
            tprev.next = t1
        return head.next