Cod sursa(job #2119591)

Utilizator hantoniusStan Antoniu hantonius Data 1 februarie 2018 14:22:36
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.06 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define MAXN 100001
using namespace std;

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

vector <int> v[MAXN];
int n, m, s, dist[MAXN], viz[MAXN];

void read()
{
    int x, y;

    fin >> n >> m >> s;
    for (int i = 0; i < m; ++i) {
        fin >> x >> y;
        v[x].push_back(y);
    }
}

void write()
{
    for (int i = 1; i <= n; ++i)
        if (dist[i] > 0 || i == s)
            fout << dist[i] << ' ';
        else
            fout << "-1 ";
    fout.close();
}

void solve()
{
    queue <int> c;
    vector <int>::iterator it;
    int aux;

    c.push(s);
    viz[s] = 1;
    while (c.empty() == false) {
        aux = c.front();
        c.pop();
        for (it = v[aux].begin(); it != v[aux].end(); ++it)
            if (viz[*it] == 0) {
                viz[*it] = 1;
                dist[*it] = dist[aux] + 1;
                c.push(*it);
            }
    }
}

int main()
{
    read();
    solve();
    write();
    return 0;
}