""" We are given the head node root of a binary tree, where additionally every node's value is either a 0 or a 1. Return the same tree where every subtree (of the given tree) not containing a 1 has been removed. (Recall that the subtree of…

We are given the head node root of a binary tree, where additionally every node's value is either a 0 or a 1. Return the same tree where every subtree (of the given tree) not containing a 1 has been removed. (Recall that the subtree of a node X is X,…

We are given the head node root of a binary tree, where additionally every node's value is either a 0 or a 1. Return the same tree where every subtree (of the given tree) not containing a 1 has been removed. (Recall that the subtree of a node X is X,…

dfs 要点是这一句: return node.val==1 or node.left or node.right 完整代码: # Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None import functools class Solution: @functools.lru_cach…

https://leetcode.com/contest/weekly-contest-79/problems/binary-tree-pruning/ -- 814 from leetcode tree traverse (post traverse) left right and root the model void traverse(node){ if(node.left!=null) traverse(node.left); if(node.right!=null) traverse(…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 后序遍历 日期 题目地址:https://leetcode.com/problems/binary-tree-pruning/description/ 题目描述 We are given the head node root of a binary tree, where additionally every node's value is eith…

1.题目描述 2.问题分析 使用递归 3.代码 TreeNode* pruneTree(TreeNode* root) { if (root == NULL) return NULL; prun(root); return root; } void prun(TreeNode *root) { if (root == NULL) return; if (!has_ones(root->left)) root->left = NULL; if (!has_ones(root->right)…

題目是說,如果左右子樹都不存在又自已為0,就去掉那個子樹(設為null) recursive後序,左子樹,右子樹,然後是根 自已同時又是別人的子樹,所以要告訢根自已是不是存在 從a開始,左右子樹都不存在,而自已是1 所以傳回true 告訢 root(c) 左子樹a 不可以刪掉(存在) b,左右子樹都不存在,而自已是0 所以傳回false 告訢 root(c) 右子樹b 可以刪掉(不存在) c,右子樹b可以刪除,把right = null,左子樹不可刪.雖然自已是0,可是左子樹存在所以傳回true…

二叉树(Binary Tree)是最简单的树形数据结构,然而却十分精妙.其衍生出各种算法,以致于占据了数据结构的半壁江山.STL中大名顶顶的关联容器--集合(set).映射(map)便是使用二叉树实现.由于篇幅有限,此处仅作一般介绍(如果想要完全了解二叉树以及其衍生出的各种算法,恐怕要写8~10篇). 1)二叉树(Binary Tree) 顾名思义,就是一个节点分出两个节点,称其为左右子节点:每个子节点又可以分出两个子节点,这样递归分叉,其形状很像一颗倒着的树.二叉树限制了每个节点最多有两个子节…

题目链接:Balanced Binary Tree | LeetCode OJ 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 tha…