Cod sursa(job #1975486)

Utilizator MaligMamaliga cu smantana Malig Data 1 mai 2017 08:28:20
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;
ifstream in("bfs.in");
ofstream out("bfs.out");

#define pb push_back
const int NMax = 1e5 + 5;
const int inf = 1e9 + 5;

int N,M,S;
bool viz[NMax];
int dist[NMax];
vector<int> v[NMax];

int main() {
    in>>N>>M>>S;

    while (M--) {
        int x,y;
        in>>x>>y;
        v[x].pb(y);
    }

    for (int i=1;i<=N;++i) {
        dist[i] = inf;
    }
    dist[S] = 0;

    queue<int> Q;
    Q.push(S);
    while (Q.size()) {
        int nod = Q.front();
        Q.pop();

        for (auto nxt : v[nod]) {
            if (viz[nxt] || dist[nxt] < dist[nod] + 1) {
                continue;
            }

            viz[nxt] = true;
            dist[nxt] = dist[nod] + 1;
            Q.push(nxt);
        }
    }

    for (int i=1;i<=N;++i) {
        out<<( (dist[i] == inf) ? -1 : dist[i])<<' ';
    }
    out<<'\n';


    in.close();out.close();
    return 0;
}