22 leetcode - Merge Two Sorted Lists

#!/usr/bin/python
# -*- coding: utf-8 -*-
'''
英文: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.
中文:合并两个有序链表
'''
# Definition for singly-linked list.
# class ListNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution(object):
def mergeTwoLists(self, l1, l2):
"""
:type l1: ListNode
:type l2: ListNode
:rtype: ListNode
"""
if not l1:
return l2
if not l2:
return l1
if l1.val < l2.val:
start = tmp = l1
l1 = l1.next
else:
start = tmp = l2
l2 = l2.next
while l1 and l2:
if l1.val < l2.val:
tmp.next = l1
l1 = l1.next
else:
tmp.next = l2
l2 = l2.next
tmp = tmp.next
if l1:
tmp.next = l1
if l2:
tmp.next = l2
return start

if __name__ == "__main__":
s = Solution()