Cod sursa(job #1889342)

Utilizator MolnarMalinaMalina MolnarMalina Data 22 februarie 2017 18:02:06
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.97 kb
#include <fstream>
#include<queue>
#include<vector>
#define inf -100000
using namespace std;
ifstream fi("bfs.in");
ofstream fo("bfs.out");
vector <int> G[100005];
queue <int> q;
int dist[100005];
bool viz[100005];
int n, m, S;

void bfs(int start)
{
    q.push(start);
    viz[start]=1;
    dist[start]=0;
    int nod;
    while(!q.empty())
    {
        nod=q.front();
        q.pop();
        for(auto it: G[nod])
            if(!viz[it])
            {
                q.push(it);
                viz[it]=true;
                dist[it]=dist[nod]+1;
            }
    }
}


int main()
{
   int x,y,i;
   fi>>n>>m>>S;
   for(i=1; i<=m; i++)
   {
       fi>>x>>y;
       G[x].push_back(y);
   }
    for(i=1; i<=n; i++)
        dist[i]=inf;
   bfs(S);
   for(i=1; i<=n; i++)
        {
            if(dist[i]==inf)
                fo<<"-1"<<" ";
            else
                fo<<dist[i]<<" ";
        }
   fi.close();
   fo.close();
}