Time: 35 ms (67.17%), Space: 13.9 MB (60.50%) - LeetHub

24-swap-nodes-in-pairs/24-swap-nodes-in-pairs.py

@@ -0,0 +1,19 @@
+# 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
+        
+        first = head
+        second = head.next
+        
+        first.next = second.next
+        second.next = first
+        
+        first.next = self.swapPairs(first.next)
+        
+        return second