Cod sursa(job #1989956)

Utilizator DavidLDavid Lauran DavidL Data 9 iunie 2017 18:38:37
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.98 kb
#include <fstream>
#include <vector>
#include <queue>
#define MAXN 100001
#define INF 1000000000
using namespace std;
ifstream fi("bfs.in");
ofstream fo("bfs.out");

vector <int> vecin[MAXN];
int D[MAXN],n,m,s,x,y;
queue <int> Q;

void parcurgere()
{
    D[s]=0;
    Q.push(s);
    while (!Q.empty())
    {
        int curent=Q.front();
        Q.pop();
        for (int i=0; i<vecin[curent].size(); i++)
        {
            if (D[curent]+1<D[vecin[curent][i]])
            {
                D[vecin[curent][i]]=D[curent]+1;
                Q.push(vecin[curent][i]);
            }
        }
    }
}

int main()
{
    fi>>n>>m>>s;
    for (int i=1; i<=m; i++)
    {
        fi>>x>>y;
        vecin[x].push_back(y);
    }
    for (int i=1; i<=n; i++)
        D[i]=INF;
    parcurgere();
    for (int i=1; i<=n; i++)
        if (D[i]==INF)
            fo<<-1<<" ";
        else
            fo<<D[i]<<" ";
    fi.close();
    fo.close();
    return 0;
}