# Question

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
```

# Solution

```
# 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:
return l2
if l2 is None:
return l1
curr1, curr2 = l1, l2
if l1.val <= l2.val:
head = l1
curr1 = l1.next
else:
head = l2
curr2 = l2.next
prev = head
while curr1 is not None and curr2 is not None:
if curr1.val <= curr2.val:
prev.next = curr1
curr1 = curr1.next
else:
prev.next = curr2
curr2 = curr2.next
prev = prev.next
if curr1 is None:
prev.next = curr2
elif curr2 is None:
prev.next = curr1
return head
```