[WEEK7]

reversed linked list solved

Author: sun912

reverse-linked-list/sun912.py

@@ -0,0 +1,20 @@
+"""
+    TC: O(n)
+    SC: O(1)
+
+"""
+
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, val=0, next=None):
+#         self.val = val
+#         self.next = next
+class Solution:
+    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        node, prev = head, None
+
+        while node:
+            next, node.next = node.next, prev
+            prev, node = node, next
+
+        return prev