Cod sursa(job #3275050)

Utilizator witekIani Ispas witek Data 9 februarie 2025 02:07:51
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.93 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

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

const int oo = 2e9;

int n, m, s;
vector <vector<int>> v;
queue <int> q;
vector <int> d;

void init() {
    v = vector<vector<int>>(n + 1);
    d = vector <int> (n + 1, oo);
}

void read() {
    fin >> n >> m >> s;
    init();
    for(int i = 1; i <= m; ++i) {
        int x, y;
        fin >> x >> y;
        v[x].push_back(y);
    }
}

void bfs(int node) {
    q.push(node);
    d[node] = 0;
    while(!q.empty()) {
       int currentNode = q.front();
       q.pop();
       for(const auto& neighbour : v[currentNode]) {
           if(d[currentNode] + 1 < d[neighbour]) {
               d[neighbour] = d[currentNode] + 1;
               q.push(neighbour);
           }
       }
    }
}

int main() {
    read();
    bfs(s);
    for(int i = 1; i <= n; ++i)
        fout << (d[i] != oo ? d[i] : -1) << " ";
}