[daiyongg-kim] WEEK 07 solutions

reverse-linked-list/daiyongg-kim.py

@@ -0,0 +1,20 @@
+# 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]:
+        curr = head
+        prev = None
+
+        # Time Complexity : O(n)
+        # Space Complexity : O(1)
+        while curr:
+            temp = curr.next
+            curr.next = prev
+            prev = curr
+            curr = temp
+
+        return prev