[转] leetcode 21.合并两个有序链表 Merge Two Sorted Lists（Python）

原作者地址

本人小白，刷leetcode第一次遇到链表题，有点晕。网上找了很多解答，结果越看越晕[捂脸]。

直到看到了这位大神的代码，豁然开朗，且非常简洁，在此记录。

代码如下：

# 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
        """
        head = ListNode(0)
        first = head
        while l1 != None and l2 != None:
            if l1.val > l2.val:
                head.next = l2
                l2 = l2.next
            else :
                head.next = l1
                l1 = l1.next
            head = head.next
        if l1 == None:
            head.next = l2
        elif l2 == None:
            head.next = l1
        return first.next