Cod sursa(job #2207464)

Utilizator andreichiricaAndrei Chirica andreichirica Data 25 mai 2018 19:13:21
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.89 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#define inf 1<<30

using namespace std;
ifstream fin("bfs.in");
ofstream fout("bfs.out");
vector <int> a[100002];
queue <int> q;
int n,m,s,x,y,p[100002];
void bfs(int v)
{

    q.push(v);
    p[v]=0;
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        for(int i=0;i<a[x].size();i++)
        {
            if(p[a[x][i]]>p[x]+1)
            {
                q.push(a[x][i]);
                p[a[x][i]]=p[x]+1;
            }
        }
    }

}
int main()
{
    fin>>n>>m>>s;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y;
        a[x].push_back(y);

    }
    for(int i=0;i<=n;i++)
        p[i]=inf;
    bfs(s);
    for(int i=1;i<=n;i++)
    {
        if(p[i]==inf)
            fout<<-1<<" ";
        else
            fout<<p[i]<<" ";
    }
    return 0;
}