Cod sursa(job #1042617)

Utilizator cminfo10Noname cminfo10 Data 27 noiembrie 2013 14:43:26
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.93 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;

#define MAXN 100010

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

int n, m, start;
vector<int> G[MAXN];
queue<int> q;
int dist[MAXN];

void bfs(int nod) {
    q.push(nod);

    while (!q.empty()) {
        int nd = q.front();
        q.pop();

        for (int i = 0; i < G[nd].size(); i++) {
            if (dist[G[nd][i]] == -1) {
                q.push(G[nd][i]);
                dist[G[nd][i]] = dist[nd] + 1;
            }
        }
    }
}

int main() {
    f >> n >> m >> start;
    for (int i = 1; i <= m; i++) {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
    }

    for (int i = 0; i <= n; i++) {
        dist[i] = -1;
    }

    dist[start] = 0;
    bfs(start);

    for (int i = 1; i <= n; i++) {
        g << dist[i] << ' ';
    }
    g << endl;

    return 0;
}