Cod sursa(job #1086833)

Utilizator gabrielvGabriel Vanca gabrielv Data 18 ianuarie 2014 16:33:46
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.13 kb
#include <cstdio>
#include <vector>
#include <queue>

using namespace std;

#define NMAX 100005

int N,M,S;
bool used[NMAX];
int Dist[NMAX];

vector < int > G[NMAX];
queue < int > Q;

void Read()
{
    freopen("bfs.in","r",stdin);
    scanf("%d%d%d",&N,&M,&S);
    for(int i=1;i<=M;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        G[x].push_back(y);
    }
}

void BFS()
{
    Q.push(S);
    used[S] = true;

    while(!Q.empty())
    {
        int nod = Q.front();
        Q.pop();
        for(unsigned j=0;j<G[nod].size();j++)
        {
            int vecin = G[nod][j];
            if(used[vecin])
                continue;

            Q.push(vecin);
            used[vecin] = true;
            Dist[vecin] = Dist[nod] + 1;
        }


    }
}

void Print()
{
    freopen("bfs.out","w", stdout);

    for(int i=1;i<=N;i++)
        if(Dist[i])
            printf("%d ",Dist[i]);
        else
            if(i==S)
                printf("0 ");
            else
                printf("-1 ");
}

int main()
{
    Read();
    BFS();
    Print();

    return 0;
}