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.
Example:
Input: 1->2->4, 1->3->4
Output: 1->1->2->3->4->4解法
# Definition for singly-linked list.
# class ListNode:
# def __init__(self, x):
# self.val = x
# self.next = None
class Solution:
def mergeTwoLists(self, l1: 'ListNode', l2: 'ListNode') -> 'ListNode':
newHead = ListNode(None)
pointer = newHead
while l1 or l2:
if l1 is not None and (l2 is None or l1.val <= l2.val):
pointer.next = l1
l1 = l1.next
else:
pointer.next = l2
l2 = l2.next
pointer = pointer.next
return newHead.next
