[leetcode] 21. merge two sorted lists

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.
## Analyze:

## Code 1 :

# 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
“””
head=ListNode(0)
tail=head
while l1 and l2:
if l1.val > l2.val:
tail.next=l2
l2=l2.next
else:
tail.next=l1
l1=l1.next
tail=tail.next
if l1 is None:
tail.next=l2
else:
tail.next=l1
return head.next

### Submission Result:
Status: Accepted
Runtime: 52 ms
Ranking: beats 97.5%