Cod sursa(job #876524)

Utilizator TeodoraTanaseTeodora Tanase TeodoraTanase Data 11 februarie 2013 21:16:53
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.08 kb
#include <cstdio>
#include <vector>
#include <queue>

#define NMAX 100001

using namespace std;

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

int n;
int v;
int d[NMAX];

void read()
{
    freopen("bfs.in", "r", stdin);

    int m;
    int x;
    int y;

    scanf("%d %d %d\n", &n, &m, &v);
    while(m --)
    {
        scanf("%d %d\n", &x, &y);
        G[x].push_back(y);
    }
}

void solve()
{
    Q.push(v);

    while(!Q.empty())
    {
        int x = Q.front();
        Q.pop();

        unsigned int m = G[x].size();
        for(unsigned int i = 0; i < m; ++ i)
        {
            int y = G[x][i];

            if(d[y] == 0 && y != v)
            {
                d[y] = d[x] + 1;
                Q.push(y);
            }
        }
    }
}

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

    for(int i = 1; i <= n; ++ i)
        if(d[i] == 0 && i != v)
            printf("-1 ");
        else
            printf("%d ", d[i]);

    printf("\n");
}

int main()
{
    read();
    solve();
    write();

    return 0;
}