Cod sursa(job #2632509)

Utilizator Vlad.Vlad Cristian Vlad. Data 3 iulie 2020 16:28:22
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.87 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
int N, M, S;
vector<vector<int>> gr;
vector<int> t;
void read() {
    int x, y;
    fin >> N >> M >> S;
    gr.resize(N + 1);
    t.resize(N + 1, 0);
    for (int i = 0; i < M; ++i) {
        fin >> x >> y;
        gr[x].push_back(y);
    }
}
void BFS(int node) {
    queue<int> q;
    q.push(node);
    int nod;
    while (!q.empty()) {
        nod = q.front();
        q.pop();
        for (auto i : gr[nod]) {
            if (t[i] == 0 && i != node) {
                q.push(i);
                t[i] = t[nod] + 1;
            }
        }
    }
}
int main()
{
    read();
    BFS(S);
    for (int i = 1; i <= N; ++i) {
        if (t[i] == 0 && i != S) {
            fout << -1 << " ";
        }
        else
            fout << t[i] << " ";
    }
    return 0;
}