合并两个有序链表

将两个有序链表合并为一个新的有序链表并返回。新链表是通过拼接给定的两个链表的所有节点组成的。

示例：

输入：1->2->4, 1->3->4
输出：1->1->2->3->4->4

# 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
"""

解答：

class ListNode(object):
     def __init__(self, x):
        self.val = x
        self.next = None

class Solution(object):
     def mergeTwoLists(self, l1, l2):
         while True:
            new_node = ListNode(0) #建立新结点
            pre_node = new_node
            while l1 and l2:
                if l1.val < l2.val:
                    pre_node.next = l1
                    l1 = l1.next
                else:
                    pre_node.next = l2
                    l2 = l2.next
                pre_node = pre_node.next
            if l1 is not None:
                 pre_node.next = l1
            if l2 is not None:
                pre_node.next = l2
            #print(pre_node.val)
            return new_node.next

head1 = ListNode(2)
n1 = ListNode(8)
n2 = ListNode(9)
n3 = ListNode(10)
head1.next = n1
n1.next = n2
n2.next = n3

#while head1:
#     print(head1.val)
    # head1 = head1.next

head2 = ListNode(4)
m1 = ListNode(5)
m2 = ListNode(6)
m3 = ListNode(10)
head2.next = m1
m1.next = m2
m2.next = m3
#while head2:
#     print(head2.val)
     #head2 = head2.next

s = Solution()
r = s.mergeTwoLists(head1,head2)
while r:
    print(r.val)
    r = r.next