Leetcode代码补全——链表

通过补全代码可以更深刻的体会到，链表就是一个存储方式，通过一单元的存储指向下一单元，而查看单元内容通过头部开始的指针依次遍历。这是leetcode里融合两个链表的题目，具体代码如下：

#encoding=utf-8

class ListNode(object):

    def __init__(self, x):

        self.val = x

        self.next = None

        self.root = None

#添加链表节点函数

    def addNode(self, val):

        if self.root==None:

            self.root= ListNode(x=val)

            return self.root

        else:

      # 有头结点，则需要遍历到尾部节点，进行链表增加操作

            cursor = self.root

            while cursor.next!= None:

                cursor = cursor.next

            cursor.next = ListNode(x=val)

            return self.root

#下面就是题目具体解决过程 

class Solution(object):

    def mergeTwoLists(self, l1, l2):

        """

        :type l1: ListNode

        :type l2: ListNode

        :rtype: ListNode

        """

        head=ListNode(0)

        cur=head

        

        while(l1!=None and l2!=None):

            if l1.val<l2.val:

                cur.next=l1

                l1=l1.next

            else:

                cur.next=l2

                l2=l2.next

            #cur.next.next=None

            cur=cur.next

        if l1!=None:

            cur.next=l1

        else:

            cur.next=l2

        return head.next

#下面也是leetcode省略部分，实例化两个链表。添加节点，进行融合操作 

a=ListNode(1)

b=ListNode(1)

print a.addNode(3).addNode(4)

print b.addNode(2).addNode(4)

c=Solution()

print c.mergeTwoLists(a,b)