【LeetCoe】21. Merge Two Sorted Lists

Problem

合并两个已排序的链接列表并将其作为新列表返回。新列表应该通过拼接前两个列表的节点来完成。

例：

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

Algorithmic thinking

pass

Python 3 solution

class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None


class Solution:
    def mergeTwoLists(self, l1: ListNode, l2: ListNode) -> ListNode:
        # dummy
        dummy = pos = ListNode(0)
        while l1 and l2:
            if l1.val <= l2.val:
                pos.next = l1
                l1 = l1.next
            else:
                pos.next = l2
                l2 = l2.next
            pos = pos.next

        pos.next = l1 or l2

        return dummy.next