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
# 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
"""
if l1 is None and l2 is None:
return l1
if l1 is None:
return l2
if l2 is None:
return l1
start = ListNode(0)
pos = start
while l1 and l2:
if l1.val<l2.val:
pos.next = l1
l1 = l1.next
pos = pos.next
else:
pos.next = l2
l2 = l2.next
pos = pos.next
if l1:
pos.next = l1
l1 = l1.next
pos = pos.next
if l2:
pos.next = l2
l2 = l2.next
pos = pos.next
return start.next