Cod sursa(job #1417148)

Utilizator MasebMateita Sebastian Maseb Data 9 aprilie 2015 18:11:22
Problema BFS - Parcurgere in latime Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 0.91 kb
#include <cstdio>
#include <vector>
#include <queue>

#define NMAX 100000
using namespace std;
vector<int> G[NMAX];
queue<int> Q;
int D[NMAX],N,M,S,i,x,y;

void bfs(int nod)
{
    for (vector<int> :: iterator itt=G[nod].begin(); itt!=G[nod].end(); ++itt)
    {
        int k = *itt;
        if (D[k]==0 && k != S)
        {
            D[k]=1 + D[nod];
            Q.push(k);
        }
    }

    while (!Q.empty())
    {
        int p = Q.front();
        Q.pop();
        bfs(p);
    }
}

int main()
{
    freopen("bfs.in", "r", stdin);
    freopen("bfs.out", "w", stdout);

    scanf("%d %d %d", &N, &M, &S);
    for (i=1; i<=M; i++)
    {
        scanf("%d %d", &x, &y);
        if (x != y) G[x].push_back(y);
    }

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

    return 0;
}