这里是从上而下的更新,可以使用最常用的先序遍历,可以参见这道题Binary Tree Preorder Traversal,这样更新下来,所有的 res[i] 就都是题目中要求的值了,参见代码如下: classSolution{public:vector<int>sumOfDistancesInTree(intN, vector<vector<int>>& edges){vector<int>res(N),count(N); vector<vector<in...
题目链接:https://leetcode.com/problems/sum-of-distances-in-tree/ 题意:给出一棵树,对于每个节点,求出其他所有节点与该节点的距离之和。节点数不超过10000。 思路:如图所示,暴力复杂度太高,考虑进行优化,如图所示,考虑一对父子节点u与v,son[u]表示以u为根节点的子树的节点个数。若已知父节点u到其他所有...
LeetCode 834.树中距离之和 Sum of distance in tree 题目虽然是hard级的,但是感觉难度其实不高。属于较为基础的树状DPDPDP 首先题目是计算以各点开始的所有距离之和。如果直接计算两点距离。最快的方案是弗洛伊德算法,这是O(N3)O(N^3)O(N3)的,直接挂 下面分析一下思路: 假设某个节点rootrootroot,令dp[ro...
LeetCode 834.树中距离之和 Sum of distance in tree LeetCode 834.树中距离之和 Sum of distance in tree 题目虽然是hard级的,但是感觉难度其实不高。属于较为基础的树状DPDPDP 首先题目是计算以各点开始的所有距离之和。如果直接计算两点距离。最快的方案是弗洛伊德算法,这是O(N3)O(N^3)O(N3)的,直接...
Can you solve this real interview question? Maximum Sum BST in Binary Tree - Given a binary tree root, return the maximum sum of all keys of any sub-tree which is also a Binary Search Tree (BST). Assume a BST is defined as follows: * The left subtree
Find the number of paths that sum to a given value. The path does not need to start or end at the root or a leaf, but it must go downwards (traveling only from parent nodes to child nodes). The tree has no more than 1,000 nodes and the values are in the range -1,000,000 to...
Given an array which consists of non-negative integers and an integer m, you can split the array into m non-empty continuous subarrays. Write an algorithm to minimize the largest sum among these m subarrays. Note:If n is the length of array, assume the following constraints are satisfied:...
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LeetCode_437. Path Sum III 437. Path Sum III Easy You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need to start or end at the root or a leaf, but it must go downwards (traveling ...
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