Cod sursa(job #2501672)

Utilizator MarianConstantinMarian Constantin MarianConstantin Data 30 noiembrie 2019 09:32:21
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.03 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define pb push_back

using namespace std;

const int MAXN = 100010;
ifstream fin("bfs.in");
ofstream fout("bfs.out");

vector<int> edges[MAXN];
queue<int> q;
bool used[MAXN];
int n, m, s, nr, cost[MAXN];

void read() {
    fin >> n >> m >> s;
    for (int i = 0; i < m; ++i) {
        int x, y;
        fin >> x >> y;
        edges[x].pb(y);
    }
}

void initialize() {
    for (int i = 1; i <= n; ++i)
        cost[i] = -1;
}

void bfs() {
    q.push(s);
    cost[s] = 0;
    used[s] = 1;
    while(!q.empty()) {
        int node = q.front();
        q.pop();
        for (const auto& it: edges[node])
            if (!used[it]) {
                cost[it] = cost[node] + 1;
                q.push(it);
                used[it] = 1;
            }
    }
}

void print() {
    for (int i = 1; i <= n; ++i)
        fout << cost[i] << ' ';
}

int main() {
    read();
    initialize();
    bfs();
    print();
    return 0;
}