update

Author: stupidjoey

206.py

@@ -0,0 +1,20 @@
+# Definition for singly-linked list.
+# class ListNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.next = None
+
+class Solution:
+    # @param {ListNode} head
+    # @return {ListNode}
+    def reverseList(self, head):
+        
+        pre_node = None
+        p = head
+        while p != None:
+            next_node = p.next
+            p.next = pre_node
+            pre_node = p
+            p = next_node
+            
+        return pre_node