re-solved reverse linked list

Author: SamTheKorean

reverse-linked-list/SamTheKorean.py

@@ -2,16 +2,26 @@
 # Space complexity : O(n)
 class Solution:
     def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        # Return None when head is None
+        if not head:
+            return None
+
         stack = []
         node = head
 
         while node:
-            stack.append(node.val)
+            stack.append(node)
             node = node.next
 
+        head = stack.pop()
         node = head
-        while node:
-            node.val = stack.pop()
+
+        # End the loop when stack is empty
+        while stack:
+            node.next = stack.pop()
             node = node.next
 
+        # Set the last node's next to None to indicate the end of the reversed list
+        node.next = None
+
         return head