BM2 链表内指定区间反转

BM/reverseBetween.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+# @author 轩辕龙儿
+# @date 2022/3/1
+# @file reverseBetween.py
+
+# class ListNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.next = None
+#
+# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
+#
+#
+# @param head ListNode类
+# @param m int整型
+# @param n int整型
+# @return ListNode类
+#
+from common import ListNode
+
+
+class Solution:
+    def reverseBetween(self, head: ListNode, m: int, n: int) -> ListNode:
+        if m == n:
+            return head
+        pre = ListNode
+        cur = head
+        pre.next = cur
+        for i in range(m - 1):
+            pre = pre.next
+            cur = cur.next
+        for i in range(n - m):
+            nxt = cur.next
+            cur.next = nxt.next
+            nxt.next = pre.next
+            pre.next = nxt
+        if m == 1:
+            return pre.next
+        else:
+            return head