문제
링크 https://leetcode.com/problems/swap-nodes-in-pairs/
Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list's nodes (i.e., only nodes themselves may be changed.)
*Example 1
Input: head = [1,2,3,4]
Output: [2,1,4,3]
*Example 2:
Input: head = []
Output: []
*Example 3:
Input: head = [1]
Output: [1]
풀이1
class Solution:
def swapPairs(self, head: Optional[ListNode]) -> Optional[ListNode]:
node=head
while node:
if (not node.val and node.val!=0) or not node.next: break
else:
node.val,node.next.val = node.next.val,node.val
node=node.next.next
return head로직
val, next.val을 이용한 직접 스왑
