ツリー・コード/ペアのノードの交換

質問する

リンク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]

答えを出す。

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 head

ろんり

val, next.val直接交換の使用