[LC] 103. Binary Tree Zigzag Level Order Traversal
发布时间:2020-12-14 04:39:04 所属栏目:大数据 来源:网络整理
导读:Given a binary tree,return the? zigzag level order ?traversal of its nodes‘ values. (ie,from left to right,then right to left for the next level and alternate between). For example: Given binary tree? [3,9,20,null,15,7] , 3 / 9 20 / 15 7
Given a binary tree,return the?zigzag level order?traversal of its nodes‘ values. (ie,from left to right,then right to left for the next level and alternate between). For example: 3 / 9 20 / 15 7 ? return its zigzag level order traversal as: [ [3],[20,9],[15,7] ] # Definition for a binary tree node. # class TreeNode(object): # def __init__(self,x): # self.val = x # self.left = None # self.right = None class Solution(object): def zigzagLevelOrder(self,root): """ :type root: TreeNode :rtype: List[List[int]] """ from collections import deque res = [] if root is None: return res is_even = False my_deque = deque() my_deque.append(root) while my_deque: size = len(my_deque) lst = [] for _ in range(size): if is_even: cur = my_deque.pop() if cur.right: my_deque.appendleft(cur.right) if cur.left: my_deque.appendleft(cur.left) else: cur = my_deque.popleft() if cur.left: my_deque.append(cur.left) if cur.right: my_deque.append(cur.right) lst.append(cur.val) res.append(lst) is_even = not is_even return res (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |