[SunaDu] Week 7

reverse-linked-list/dusunax.py

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+'''
+# 206. Reverse Linked List
+
+iterate through the linked list and reverse the direction of the pointers.
+
+## Time and Space Complexity
+
+```
+TC: O(n)
+SC: O(1)
+```
+'''
+class Solution:
+    def reverseList(self, head: Optional[ListNode]) -> Optional[ListNode]:
+        prev = None
+        current = head
+
+        while current is not None: # TC: O(n)
+            next_list_temp = current.next
+            current.next = prev
+            prev = current
+            current = next_list_temp
+
+        return prev