[LeetCode] Minimum Spanning Tree Given a list of Connections, which is the Connection class (the city name at both ends of the edge and a cost between them), find edges that can connect all the cities and spend the least amount. Return the connects if can connect all the cities, otherw...
LeetCode 1135. Connecting Cities With Minimum Cost 一道常规求minimum spanning tree的题,返回值为最小cost,出现在热带雨林厂的OA中。 难度:medium 算法:Kruskal,并查集 思路: 求MST用Kruskal或者Prim,理论上Prim在非常dense的graph中更快一点,否则Kruskal更快也更简单。 这里采用Kruskal,先对边排序,每次连最小边,...
MST(Minimum Spanning Tree,最小生成树)问题有两种通用的解法,Prim算法就是其中之一,它是从点的方面考虑构建一颗MST,大致思想是:设图G顶点集合为U,首先任意选择图G中的一点作为起始点a,将该点加入集合V,再从集合U-V中找到另一点b使得点b到V中任意一点的权值最小,此时将b点也加入集合V;以此类推,现在的集合...
Can you solve this real interview question? Minimum Time to Collect All Apples in a Tree - Given an undirected tree consisting of n vertices numbered from 0 to n-1, which has some apples in their vertices. You spend 1 second to walk over one edge of the
Can you solve this real interview question? Second Minimum Node In a Binary Tree - Given a non-empty special binary tree consisting of nodes with the non-negative value, where each node in this tree has exactly two or zero sub-node. If the node has two s
https://leetcode.com/problems/minimum-height-trees/ 有trick 对graph不熟悉。再看几遍。 参考http://bookshadow.com/weblog/2015/11/26/leetcode-minimum-height-trees/ 基本思路是“逐层删去叶子节点,直到剩下根节点为止” 有点类似于拓扑排序
[leetcode] 310. Minimum Height Trees Description For an undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a rooted tree. Among all possible rooted trees, those with minimum height are called minimum height trees (MHTs). Given such a ...
LeetCode 111 题,Minimum Depth of Binary Tree 解题思路 1、读题,求解二叉树的最小Depth。 2、用bfs 去解决,队列带上每层的层数。当有一个节点的左右子树都为空时,返回当前层数,就找到解。 Python 代码 # De…
1 这种题还是得遍历完整个树才行,我总想着边走就边得到这个值了 2 root等于None的时候,是直接return,并不是返回-1 3 root值是global smallest 4 二叉树有时需要写一个子函数 5 因为有个全局最小,那就设置一个全局最大,每次更新那个全局最大数,直到traverse完所有的节点...
Lec 31 - Minimum Spanning Trees MST, Cut Property, Generic MST Algorithm Prim's Algorithm Kruskal's Algorithm 一个Warm-up question: 给定一个graph,判断里面有没有cycle。 方案1:直接遍历,如果遍历到了marked的点,就说明有cycle。需要O(V+E)的复杂度... 查看原文 the minimal spanning tree algorithm ...