21. Merge Two Sorted Lists

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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

解法

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def mergeTwoLists(self, l1: 'ListNode', l2: 'ListNode') -> 'ListNode':
        
        newHead = ListNode(None)
        pointer = newHead

        while l1 or l2:            
            if l1 is not None and (l2 is None or l1.val <= l2.val):
                pointer.next = l1
                l1 = l1.next
            else:
                pointer.next = l2
                l2 = l2.next

            pointer = pointer.next

        return newHead.next

发表至：leetcode

2019-02-11

# leetcode