[변지협] Day27

leetcode3/변지협/206. Reverse Linked List.py

@@ -0,0 +1,42 @@
+'''
+1. 아이디어 :
+2. 시간복잡도 :
+    O(n)
+3. 자료구조/알고리즘 :
+'''
+
+# 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]:
+        """
+        :type head: Optional[ListNode]
+        :rtype: Optional[ListNode]
+        """
+        if head == None:
+            return None
+        temp = []
+        _next = head
+        while True:
+            val = _next.val
+            _next = _next.next
+
+            temp.append(val)
+
+            if _next is None:
+                break
+
+        # temp = temp[::-1]
+        prev = None
+        for i in range(len(temp)):
+            # if prev is not None:
+                # print(prev.val)
+            prev = ListNode(val=temp[i], next=prev)
+
+        print(prev.next, prev.val)
+
+        return prev
+