参考代码:
class ListNode:
def __init__(self, val):
self.val = val
self.next = None
class Solution:
def mergeTwoLists(self, l1, l2):
dummy = ListNode(0)
tmp = dummy
while l1 != None and l2 != None:
if l1.val < l2.val:
tmp.next = l1
else:
tmp.next = l2
l2 = l2.next
tmp = tmp.next
if l1 != None:
tmp.next = l1
else:
tmp.next = l2
return dummy.next