2020-05-10

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 root.

Input Specification:

Each input file contains one test case. For each case, the first line contains a positive integer N (≤104) which is the number of nodes, and hence the nodes are numbered from 1 to N. Then N−1 lines follow, each describes an edge by given the two adjacent nodes' numbers.

Output Specification:

For each test case, print each of the deepest roots in a line. If such a root is not unique, print them in increasing order of their numbers. In case that the given graph is not a tree, print Error: K components where K is the number of connected components in the graph.

Sample Input 1:

5
1 2
1 3
1 4
2 5

      
    

Sample Output 1:

3
4
5

      
    

Sample Input 2:

5
1 3
1 4
2 5
3 4

      
    

Sample Output 2:

Error: 2 components

#include
#include
#include
using namespace std;
int n;
int maxheight = 0;
vector> v;
bool visit[10010];
vector temp;
set s;
void dfs(int node,int height){
    if(height>maxheight){
        temp.clear();
        temp.push_back(node);
        maxheight = height;
    }else if(height==maxheight){
        temp.push_back(node);
    }
    visit[node] = true;
    for(int i=0;i=2){
        printf("Error: %d components",cnt);
    }else{
        temp.clear();
        maxheight = 0;
        fill(visit,visit+10010,false);
        dfs(e,1);
        for(int j=0;j