2019-12-29 430. Flatten a Multilevel Doubly Linked List

ruicore · ruicore · commit fdc9cad0866f · 2019-12-29T11:07:48.000+08:00
diff --git a/LeetCode/2019-12-29-430-Flatten-a-Multilevel-Doubly-Linked-List.py b/LeetCode/2019-12-29-430-Flatten-a-Multilevel-Doubly-Linked-List.py
@@ -0,0 +1,33 @@
+# -*- coding: utf-8 -*-
+# @Author:             何睿
+# @Create Date:        2019-12-29 10:57:03
+# @Last Modified by:   何睿
+# @Last Modified time: 2019-12-29 11:05:17
+
+
+class Node:
+    def __init__(self, val, prev, next, child):
+        self.val = val
+        self.prev = prev
+        self.next = next
+        self.child = child
+
+
+class Solution:
+    def flatten(self, head: 'Node') -> 'Node':
+        current = head
+        while current:
+            if current.child:
+                _next = current.next  # 当前节点的后一个节点
+                last = current.child  # 当前节点的自节点
+                while last.next:
+                    last = last.next  # 如果有子节点，找到子节点的最后一个节点
+                current.next = current.child
+                current.next.prev = current  # 将自节点向上提高一层
+                current.child = None
+                last.next = _next
+                if _next:
+                    _next.prev = last
+            current = current.next
+
+        return head
