leetcode 430. Flatten a Multilevel Doubly Linked List

发表于 | 分类于

题目链接：leetcode

思路：
链表

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
"""
# Definition for a Node.
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):
        """
        :type head: Node
        :rtype: Node
        """
        stack,cur = [],head
        while cur:
            if cur.child:
                if cur.next:
                    stack.append(cur.next)
                cur.next,cur.child.prev,cur.child = cur.child,cur,None
            if not cur.next and len(stack) >0:
                tmp = stack.pop()
                tmp.prev,cur.next = cur,tmp
            cur = cur.next
        return head