Cod sursa(job #797046)

Utilizator ucnahHancu Andrei ucnah Data 13 octombrie 2012 11:18:23
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.97 kb
#include <cstdio>
#include <queue>
#include <vector>
#include <cstring>
#define N 100005
using namespace std;
int c[N],viz[N];
int n,m,start;
queue <int> Q;
vector <int> a[N];
void citire()
{
    freopen("bfs.in","r",stdin);
    scanf("%d %d %d",&n,&m,&start);
    for(int i=0;i<m;i++)
    {
        int x,y;
        scanf("%d %d",&x,&y);
        a[x].push_back(y);
    }
}
void bfs(int v)
{
    memset(c,-1,sizeof(c));
    c[v]=0;
    viz[v]=1;
    Q.push(v);
    while(!Q.empty())
    {
        int x=Q.front();
        for(int j=0;j<a[x].size();j++)
        {
            if(!viz[a[x][j]])
            {
                viz[a[x][j]]=1;
                c[a[x][j]]=1+c[x];
                Q.push(a[x][j]);
            }
        }
        Q.pop();
    }
}
void afisare()
{
    freopen("bfs.out","w",stdout);
    for(int i=1;i<=n;i++)
        printf("%d ",c[i]);
}
int main()
{
    citire();
    bfs(start);
    afisare();
    return 0;
}