Create swap_every_two_nodes.py

linked_lists/swap_every_two_nodes.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+
+class ListNode:
+  def __init__(self, val=0, next=None):
+      self.val = val
+      self.next = next
+
+
+def swap_pairs(head: Optional[ListNode]) -> Optional[ListNode]:
+      if not head or not head.next:
+          return head
+
+      ## nodes to be swapped
+      first_node = head
+      second_node = head.next
+
+      # swapping
+      first_node.next = swap_pairs(second_node.next)
+      second_node.next = first_node
+
+      return second_node