Cod sursa(job #2032209)

Utilizator alextodoranTodoran Alexandru Raul alextodoran Data 4 octombrie 2017 18:22:03
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define NM 100002
using namespace std;

vector <int> gr[NM];
queue <int> q;

int n, m, S, a, b, d[NM], f;

void bfs(int n)
{
    q.push(n);
    d[n] = 0;
    while(!q.empty())
    {
        f = q.front();
        q.pop();
        for(auto i:gr[f])
        {
            if(d[i] > d[f] + 1)
            {
                d[i] = d[f] + 1;
                q.push(i);
            }
        }
    }
}

int main()
{
    ifstream fin ("bfs.in");
    ofstream fout ("bfs.out");
    fin >> n >> m >> S;
    for(int i = 1; i <= n; i++)
        d[i] = NM;
    for(int i = 1; i <= m; i++)
    {
        fin >> a >> b;
        gr[a].push_back(b);
    }
    bfs(S);
    for(int i = 1; i <= n; i++)
        if(d[i] != 100002)
            fout << d[i] << " ";
        else
            fout << -1 << " ";
    return 0;
}