A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: E…

A graph which is connected and acyclic can be considered a tree. The hight of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: Ea…

A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: E…

题目 A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification…

[题目大意] 给出n个结点和n-1条边,问它们能否形成一棵n个结点的树,如果能,从中选出结点作为树根,使整棵树的高度最大.输出所有满足要求的可以作为树根的结点. [思路] 方法一:模拟. 1 连通.边数为n-1的图一定是一棵树.因此先判断连通图个数(用DFS遍历图,从而计算连通图个数),等于1则能形成一棵树. 2 遍历每一个节点,假设它为根节点构造一棵树. 方法二: 1 由于连通.边数为n-1的图一定是一棵树,因此需要判断给定数据是否能使图连通.2 确定图连通后,则确定了树,选择合适根结点使树高…

Source: PAT A1021 Deepest Root (25 分) Description: A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root…

A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: E…

题目如下: A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specificat…

1021. Deepest Root (25) 时间限制 1500 ms 内存限制 65536 kB 代码长度限制 16000 B 判题程序 Standard 作者 CHEN, Yue A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root t…

A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: E…

https://pintia.cn/problem-sets/994805342720868352/problems/994805482919673856 A graph which is connected and acyclic can be considered a tree. The hight of the tree depends on the selected root. Now you are supposed to find the root that results in a…

1021 Deepest Root (25)(25 分) A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest…

Deepest Root A graph which is connected and acyclic can be considered a tree. The hight of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Spec…

problem A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specific…

PAT甲级1021. Deepest Root 题意: 连接和非循环的图可以被认为是一棵树.树的高度取决于所选的根.现在你应该找到导致最高树的根.这样的根称为最深根. 输入规格: 每个输入文件包含一个测试用例.对于每种情况, 第一行包含正整数N(<= 10000),它是节点的数量,因此节点从1到N编号.然后按N-1行,每个都通过给定两个相邻节点的数字来描述一个边. 输出规格: 对于每个测试用例,打印一行中最深的根.如果这样的根不是唯一的, 打印他们的数字增加的顺序.在给定的图形不是树的情况下,打…

1021. Deepest Root (25) 时间限制 1500 ms 内存限制 65536 kB 代码长度限制 16000 B 判题程序 Standard 作者 CHEN, Yue A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root t…

1021 Deepest Root (25)(25 分)A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest…

http://pat.zju.edu.cn/contests/pat-a-practise/1021 无环连通图也可以视为一棵树,选定图中任意一点作为根,如果这时候整个树的深度最大,则称其为 deepest root. 给定一个图,按升序输出所有 deepest root.如果给定的图有多个连通分量,则输出连通分量的数量. 1.使用并查集判断图是否为连通的. 2.任意选取一点,做 dfs 搜索,选取其中一个最远距离的点 A,再做一次 dfs,找到的所有距离最远的点以及点 A 都是 deepest…

A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: E…

1021 Deepest Root (25 分)   A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest r…

A graph which is connected and acyclic can be considered a tree. The height of the tree depends on the selected root. Now you are supposed to find the root that results in a highest tree. Such a root is called the deepest root. Input Specification: E…

#include <cstdio> #include <cstdlib> #include <vector> using namespace std; class Node { public: vector<int> adj; bool visited; Node() : visited(false) {} }; void reset_nodes(vector<Node>& nodes) { int len = nodes.size();…

先并查集判断连通性,然后暴力每个点作为根节点判即可. #include<iostream> #include<cstring> #include<cmath> #include<algorithm> #include<cstdio> #include<queue> #include<vector> using namespace std; struct Edge { int a,b; }e[]; ],dep,U; ]; v…

第一次出现超时 ac不了的题 思路一:对于每个节点用一次dfs dfs中 记录到当前的最长路径,若大于最长,则清除set,并加入当前节点 思路二:先查找只有一个相邻节点的节点进行dfs,由于可能存在闭环,对为访问的节点dfs 思路三:(TQL),大神思路,先以1节点为根用一次dfs(1),求出以1为根的最深点集合,并且完成深度搜索一次,可以知道是否还有不可达点, 如果还有没访问,继续遍历,可以的到连通分量数. 如果大于1,直接打印错误信息 否则,对最深点集合的其中一个进行dfs 即为答案. //…

这道题的关键在于如何求两个最远的结点,二叉树比较容易一直DFS就能找到,但是普通树就比较麻烦.要先找到一端,再去找另外一端,两端的并集就是答案.因为结点都是对称的,所以两端都是答案.还要注意去重,12 13这种就会重复. #include<bits/stdc++.h> using namespace std; ; vector<int>pre[maxn]; int n; bool vis[maxn]; vector<int>ans; void DFS(int s) {…

dfs求最大层数并查集求连通个数 #include <iostream> #include <cstdio> #include <algorithm> #include <string.h> #include <string> #include <vector> using namespace std; /* dfs求最大层数 并查集求连通个数 */ +; int n; ; //最大层数 vector<int>deepro…

之前不知道怎么判断是不是树,参考了 http://blog.csdn.net/eli850934234/article/details/8926263 但是最后有一个测试点有超时,在bfs里我用了数组拷贝,所以简化成直接访问超时就没有了. #include <iostream> #include <vector> #include <queue> #include <cstring> using namespace std; int bing[10005];…

题意: 输入一个正整数N(N<=10000),然后输入N-1条边,求使得这棵树深度最大的根节点,递增序输出.如果不是一棵树,输出这张图有几个部分. trick: 时间比较充裕数据可能也不是很极限,所以用了一个暴力的手段.直接枚举度数为1的点进行深度优先搜索,如果递归了一万次还没有return就当它有环.(这道题的数据不存在只有一个带有自环的部分,即如有自环图必定不止一个)正解应当是dfs一次以后找到一些可能是最深根的叶子结点们,然后对这些叶子节点们依次dfs,再找到对应的一些叶子节点们.成对的叶…

Source: PAT (Advanced Level) Practice Reference: [1]胡凡,曾磊.算法笔记[M].机械工业出版社.2016.7 Outline: 基础数据结构: 线性表:栈,队列,链表,顺序表 树:二叉树的建立,二叉树的遍历,完全二叉树,二叉查找树,平衡二叉树,堆,哈夫曼树 图:图的存储和遍历 经典高级算法: 深度优先搜索,广度优点搜索,回溯剪枝 贪心,并查集,哈希映射 最短路径(只考察过单源),拓扑排序(18年9月第一次涉及相关概念,未正式考过),关键路径(未…

专题一  字符串处理 A1001 Format(20) #include<cstdio> int main () { ]; int a,b,sum; scanf ("%d %d",&a,&b); sum=a+b; ) { printf ("-"); sum=-sum; } ; ) { s[top++]=; } ) { s[top++]=sum%; sum/=; } ;i>=;i--) { printf ("%d"…