Cod sursa(job #1836477)

Utilizator hantoniusStan Antoniu hantonius Data 28 decembrie 2016 13:44:30
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.96 kb
#include <fstream>
#include <vector>
#define maxn 100002
using namespace std;

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

vector <int> g[maxn];
int viz[maxn], dist[maxn], n, m, s;

void read()
{
    int x, y;

    fin >> n >> m >> s;
    for (int i = 0; i < m; i++) {
        fin >> x >> y;
        g[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" << ' ';
}

void solve()
{
    int p, u, c[maxn], aux;
    vector <int>::iterator it;

    viz[s] = 1;
    p = u = 1;
    c[u] = s;
    while (p <= u) {
        aux = c[p++];
    for (it = g[aux].begin(); it != g[aux].end(); it++)
        if (viz[*it] == 0) {
            viz[*it] = 1;
            dist[*it] = dist[aux] + 1;
            c[++u] = *it;
        }
    }
}

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