Cod sursa(job #1213682)

Utilizator misu007Pogonaru Mihai misu007 Data 28 iulie 2014 19:48:53
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.17 kb
#include <cstdio>
#include <queue>
using namespace std;

int n,m,s,d[100001],v[100001];
struct nod
{
    int x;
    nod *u;
}*a[100001];

void read()
{
    freopen("bfs.in","r",stdin);
    int x;
    nod *nd;
    scanf("%d%d%d",&n,&m,&s);
    while(m)
    {
        --m;
        scanf("%d",&x);
        nd=new nod;
        nd->u=a[x];
        a[x]=nd;
        scanf("%d",&x);
        nd->x=x;
    }
}

void bfs(int x)
{
    queue <int> q;
    nod *nd;
    q.push(x);
    v[x]=1;
    while(!q.empty())
    {
        nd=a[q.front()];
        while(nd)
        {
            if(!v[nd->x])
            {
                v[nd->x]=1;
                q.push(nd->x);
                d[nd->x]=d[q.front()]+1;
            }
            nd=nd->u;
        }
        q.pop();
    }
}

void write(int x)
{
    freopen("bfs.out","w",stdout);
    int i;
    for(i=1;i<x;++i)
    {
        if(!d[i]) printf("-1 ");
        else printf("%d ",d[i]);
    }
    printf("0 ");
    for(i=x+1;i<=n;++i)
    {
        if(!d[i]) printf("-1 ");
        else printf("%d ",d[i]);
    }
}

int main()
{
    read();
    bfs(s);
    write(s);
    return 0;
}