pre+next；切断

CodingProgrammer · web-flow · commit 40f4c0470b61 · 2020-12-08T19:32:32.000+08:00
diff --git a/newcoder/反转链表.py b/newcoder/反转链表.py
@@ -0,0 +1,44 @@
+'''
+Descripttion: 反转链表
+version: 1
+Author: Jason
+Date: 2020-12-08 14:24:37
+LastEditors: Jason
+LastEditTime: 2020-12-08 17:54:27
+'''
+
+# -*- coding:utf-8 -*-
+# class ListNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.next = None
+
+
+class Solution:
+    # 返回ListNode
+    def ReverseList(self, pHead):
+        # write code here
+        if not pHead:
+            return pHead
+        pre_node = None
+        next_node = None
+        while pHead:
+            next_node = pHead.next
+            pHead.next = pre_node
+            pre_node = pHead
+            pHead = next_node
+        return pre_node
+
+    def ReverseList2(self, pHead):
+        # 用了额外的内存空间
+        if not pHead:
+            return pHead
+        cur = pHead
+        nodes = list()
+        while cur:
+            nodes.append(cur)
+            cur = cur.next
+        for i in range(len(nodes) - 1, 0, -1):
+            nodes[i].next = nodes[i - 1]
+        nodes[0].next = None
+        return nodes[-1]
