Cod sursa(job #2461570)

Utilizator lucaperjuLuca Perju Verzotti lucaperju Data 25 septembrie 2019 20:45:50
Problema Diametrul unui arbore Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.94 kb
#include <fstream>
#include <vector>
using namespace std;
ifstream cin ("darb.in");
ofstream cout ("darb.out");
vector <int> v[100005];
int viz[100005],cnt,q[100005],n;
int bfs (int nod)
{
    cnt=1;
    int st=1,dr=1;
    q[st]=nod;
    for(int i=1;i<=n;++i)
        viz[i]=0;
    viz[nod]=1;
    while(st<=dr)
    {
        int nc=q[st++];
        for(int i=0;i<v[nc].size();++i)
        {
            int nn=v[nc][i];
            if(!viz[nn])
            {
                viz[nn]=1+viz[nc];
                q[++dr]=nn;
            }
        }
    }
    return q[dr];
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0),cout.tie(0);
    long long i,j,m,k=0,t,s=0,rz=0,fva=0,fvb=0;
    cin>>n;
    for(i=1;i<n;++i)
    {
        int a,b;
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    int nod1=bfs(1);
    int nod2=bfs(nod1);
    cout<<viz[nod2];
    return 0;
}