Cod sursa(job #3140872)

Utilizator Mihai_PopescuMihai Popescu Mihai_Popescu Data 10 iulie 2023 13:35:47
Problema Diametrul unui arbore Scor 50
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.17 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

#define NMAX 100005

vector<int> A[NMAX];

int lung[NMAX];
queue<int> Q;

void bfs(int start, int n) {
    for (int i = 1; i <= n; ++i) {
        lung[i] = 0;
    }

    lung[start] = 1;
    Q.push(start);

    while (Q.size()) {
        int nod = Q.front();
        Q.pop();

        for (auto it : A[nod]) {
            if (lung[it] == 0) {
                lung[it] = lung[nod] + 1;
                Q.push(it);
            }
        }
    }
}

int main() {
    int n;
    fin >> n;
    for (int i = 1; i < n; ++i) {
        int a, b;
        fin >> a >> b;
        A[a].push_back(b);
        A[b].push_back(a);
    }

    int maxim = -1;
    for (int i = 1; i <= n; ++i) {
        int grad = 0;
        for (auto it : A[i]) {
            grad++;
        }
        if (grad == 1) {
            bfs(i, n);
            for (int i = 1; i <= n; ++i) {
                if (lung[i] > maxim) {
                    maxim = lung[i];
                }
            }
        }
    }

    fout << maxim;
    return 0;
}