Cod sursa(job #642781)

Utilizator toniobFMI - Barbalau Antonio toniob Data 2 decembrie 2011 10:27:27
Problema BFS - Parcurgere in latime Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 0.97 kb
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

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

int n, m, s, v[100000];
vector <int> a[100000];
queue <int> q;

void citire () {
    in >> n >> m >> s;
    int x,y;
    for (int i = 1; i <= m; ++i) {
        in >> x >> y;
        a[x].push_back(y);
    }
}

void bfs () {
    q.push(s);
    v[s]=1;
    int x, y;
    while (!q.empty()) {
        x = q.front();
        q.pop();
        for (size_t i = 0; i < a[x].size(); ++i) {
            y = a[x][i];
            if (v[y]) {
                continue;
            }
            v[y] = v[x] + 1;
            q.push (y);
        }
    }
}

void afisare () {
    for (int i = 1; i <= n; ++i) {
        if (i == s) {
            out << "0 ";
            continue;
        }
        out << v[i] - 1 << ' ';
    }
    out << '\n';
}

int main () {
    citire ();

    bfs ();

    afisare ();

    return 0;
}