LeetCode重点题系列之【21. Merge Two Sorted Lists】

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

 two pointer idea.

class Solution(object):
    def mergeTwoLists(self, l1, l2):
        """
        :type l1: ListNode
        :type l2: ListNode
        :rtype: ListNode
        """
        dummy=ListNode(0)
        cur=dummy
        while l1 and l2:
            if l1.val<l2.val:
                cur.next=l1
                l1=l1.next
            else:
                cur.next=l2
                l2=l2.next
            cur=cur.next
        if l1:
            cur.next=l1
        if l2:
            cur.next=l2
        return dummy.next