Cod sursa(job #933808)

Utilizator visanrVisan Radu visanr Data 30 martie 2013 12:38:36
Problema BFS - Parcurgere in latime Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <cstdio>
#include <cstdlib>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;

#define Nmax 100010
#define forit(it, v) for(typeof((v).begin()) it = (v).begin(); it != (v).end(); ++ it)
#define pb push_back
#define Inf 0x3f3f3f3f

int N, M, S, X, Y, Dist[Nmax];
vector<int> G[Nmax];
bool Used[Nmax];

void BFS()
{
    for(int i = 1; i <= N; ++ i) Dist[i] = Inf;
    Dist[S] = 0;
    queue<int> Q;
    Q.push(S);
    Used[S] = 1;
    while(!Q.empty())
    {
        int Node = Q.front();
        Q.pop();
        forit(it, G[Node])
            if(!Used[*it])
            {
                Dist[*it] = Dist[Node] + 1;
                Q.push(*it);
            }
    }
    for(int i = 1; i <= N; ++ i)
        if(Dist[i] == Inf) printf("-1 ");
        else printf("%i ", Dist[i]);
}

int main()
{
    freopen("bfs.in", "r", stdin);
    freopen("bfs.out", "w", stdout);
    int i;
    scanf("%i %i %i", &N, &M, &S);
    for(i = 1; i <= M; ++ i)
    {
        scanf("%i %i", &X, &Y);
        G[X].pb(Y);
    }
    BFS();
    return 0;
}