Cod sursa(job #2105955)

Utilizator ZenoTeodor Anitoaei Zeno Data 14 ianuarie 2018 17:55:34
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.89 kb
#include <bits/stdc++.h>
#define NMAX 100001
#define INF 1<<30

using namespace std;

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

vector<int> G[NMAX];
int n, m, S, a, b;
int V[NMAX];
bool use[NMAX];
queue<int> Q;

void BFS() {
    while(!Q.empty()) {
        int node = Q.front();
        Q.pop();
        for(int i = 0; i < G[node].size(); i++) {
            if(!use[G[node][i]]) {
                V[G[node][i]] = V[node] + 1;
                Q.push(G[node][i]);
                use[G[node][i]] = 1;
            }
        }
    }
}

int main()
{
    fin >> n >> m >> S;
    while(m--) {
        fin >> a >> b;
        G[a].push_back(b);
    }
    Q.push(S);
    use[S] = 1;
    BFS();
    for(int i = 1; i <= n; i++) {
        if(i == S) fout << 0 << ' ';
        else if(V[i] == 0) fout << -1 << ' ';
        else fout << V[i] << ' ';
    }
    return 0;
}