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 日期 题目地址:https://leetcode.com/problems/binary-tree-cameras/ 题目描述 Given a binary tree, we install cameras on the nodes of the tree. Each camera at a node can monitor its parent,…

968. Binary Tree Cameras 思路:如果子节点只能覆盖到父节点.当前节点,但是父节点可以覆盖到他的父节点.子节点.当前节点,所以从叶子节点往上考虑 0代表子节点没有被覆盖 1代表子节点被覆盖,但是子节点没有camera 2代表子节点被覆盖,子节点有camera https://www.cnblogs.com/ethanhong/p/10200550.html /** * Definition for a binary tree node. * struct TreeNode…

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 递归 日期 题目地址:https://leetcode.com/problems/maximum-binary-tree-ii/ 题目描述 We are given the root node of a maximum tree: a tree where every node has a value greater than any other v…

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 Java解法 Python解法 日期 题目地址:https://leetcode.com/problems/binary-tree-tilt/#/description 题目描述 Given a binary tree, return the tilt of the whole tree. The tilt of a tree node is def…

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 递归 迭代 日期 题目地址:https://leetcode.com/problems/binary-tree-paths/#/description 题目描述 Given a binary tree, return all root-to-leaf paths. Note: A leaf is a node with no children. Ex…

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 日期 题目地址: https://leetcode.com/problems/complete-binary-tree-inserter/description/ 题目描述 A complete binary tree is a binary tree in which every level, except possibly the last, i…

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…

104. Maximum Depth of Binary Tree -- Easy 方法 使用递归 /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: int…

Given a binary tree, we install cameras on the nodes of the tree. Each camera at a node can monitor its parent, itself, and its immediate children. Calculate the minimum number of cameras needed to monitor all nodes of the tree. Example 1: Input: [0,…

解题思路: 由于叶子节点一定不要安装监视器,这样才能使总监视器数量比较少,因此需要从下往上进行判断当前节点的状态(共:3种状态): 0: 当前节点安装了监视器 1: 当前节点可观,但没有安装监视器 2: 当前节点不可观 对于空节点,我们认为是可观,但没有安装监视器,因此,叶子节点就为不可观的了,设想一个节点的左右孩子(为空)都可观且没有安装监视器,那该节点必然是不可观即2 有了以上对空节点和叶子节点的处理,我们再来正式分析非终端节点: 若一个节点的左孩子或右孩子不可观,那么该节点必然不可观,需要…