solve: reverseLinkedList

Author: GaggleHelena

reverse-linked-list/yolophg.py

@@ -0,0 +1,14 @@
+# Time Complexity: O(n)
+# Space Complexity: O(1)
+
+class Solution:
+    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        prev = None
+        # to traverse the original list, starting from head
+        current = head
+        while current:
+            # reverse the link and move to the next node
+            prev, prev.next, current = current, prev, current.next
+
+        # prev is now the head of the reversed list
+        return prev