否则,我们应访访问当前节点的右孩子(入栈)。 // C++ CODE: classSolution {public: vector<int> postorderTraversal(TreeNode*root) { stack<TreeNode*>s; vector<int>result;while(root){ s.push(root); root= root->left; }while(!s.empty()){ TreeNode* tmp =s.top();if(tmp->right){if(resu...
#Definition for a binary tree node.#class TreeNode(object):#def __init__(self, x):#self.val = x#self.left = None#self.right = None"""利用堆栈先进后出的特点"""classSolution(object):defpreorderTraversal(self, root):""":type root: TreeNode :rtype: List[int]"""result=[] slack=...
LeetCode 110. Balanced Binary Tree Description Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as: a binary tree in which the depth of the two subtrees of every node never differ by more than 1. Example 1: Given the ...
Left != nil || root.Right != nil { return root } // 此时当前子树中的所有子结点都是 0 ,需要修剪掉 return nil } 题目链接: Binary Tree Pruning: leetcode.com/problems/b 二叉树剪枝: leetcode.cn/problems/bi LeetCode 日更第 235 天,感谢阅读至此的你 欢迎点赞、收藏鼓励支持小满...
Can you solve this real interview question? Lowest Common Ancestor of a Binary Tree - Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia [https://en.wikipedia.org/wi
图片来源:https://leetcode.com/articles/binary-tree-right-side-view/ 对于时间复杂度来说,基本上都是O(n),因为要访问所有的点。 对于空间复杂度来说,BFS取决于扫描过程中每层的node数,就是树的宽度,而DFS取决于扫描过程中树的深度。最坏情况两个都是O(n)。
题目:Invert a binary tree. 思路:翻转二叉树,刚开始陷入了一个思维怪圈,认为先正向保存值至一个列表,然后再按照逆向还原这个链表,这种思路太复杂,如果是对...
leetcode 107. Binary Tree Level Order Traversal II Given a binary tree, return thebottom-up level ordertraversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example: Given binary tree[3,9,20,null,null,15,7],...
Leetcode: Closest Binary Search Tree Value empty binary search tree and a target value, find the value in the BST that is closest to the target. Note: Given target value is a floating point. You are guaranteed to have only one unique value in the BST that is closest to the target....
提交网址:https://leetcode.com/problems/invert-binary-tree/ Total Accepted:84040Total Submissions:186266Difficulty:EasyACrate:45.1% Invert a binary tree. 4 / \ 2 7 / \ / \ 1 3 6 9 to 4 / \ 7 2 / \ / \ 9 6 3 1 Trivia:This problem was inspired bythis original tweetbyMax Howel...