题目描述：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.
其实题目理解起来很简单，就是讲两个有序的链表合并成一个新的链表。
1 def mergeTwoLists(self, l1, l2):
2 if l1 == None:
3 return l2
4 elif l2 == None:
5 return l1
6 elif l1 == None and l2 == None:
7 return None
8 else:
9 p1 = l1
10 p2 = l2
11 if p1.val > p2.val:
12 l = p2
13 p = p2
14 p2 = p2.next
15 while p1 and p2:
16 if p1.val > p2.val:
17 p.next = p2
18 p = p2
19 p2 = p2.next
20
21 else:
22 p.next = p1
23 p = p1
24 p1 = p1.next
25
26 if p1:
27 while p1:
28 p.next = p1
29 p = p1
30 p1 = p1.next
31 return l
32 if p2:
33 while p2:
34 p.next = p2
35 p = p2
36 p2 = p2.next
37 return l
38 else:
39 l = p1
40 p = p1
41 p1 = p1.next
42 while p1 and p2:
43 if p1.val > p2.val:
44 p.next = p2
45 p = p2
46 p2 = p2.next
47
48 else:
49 p.next = p1
50 p = p1
51 p1 = p1.next
52
53 if p1:
54 while p1:
55 p.next = p1
56 p = p1
57 p1 = p1.next
58 return l
59 if p2:
60 while p2:
61 p.next = p2
62 p = p2
63 p2 = p2.next
64 return l
