python3 解法, 执行用时: 36 ms, 内存消耗: 16.1 MB, 提交时间: 2023-08-06 11:24:00

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def swapPairs(self, head: Optional[ListNode]) -> Optional[ListNode]:
        if head == None or head.next == None:
            return head
    
        newHead = head.next
        head.next = self.swapPairs(newHead.next)
        newHead.next = head
        return newHead

golang 解法, 执行用时: 0 ms, 内存消耗: 2.1 MB, 提交时间: 2021-08-10 09:57:50

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
func swapPairs(head *ListNode) *ListNode {
    if head == nil || head.Next == nil {
        return head
    }
    newHead := head.Next
    head.Next = swapPairs(newHead.Next)
    newHead.Next = head
    return newHead
}