Cod sursa(job #1767985)

Utilizator tziplea_stefanTiplea Stefan tziplea_stefan Data 29 septembrie 2016 23:07:12
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.01 kb
#include <fstream>
#include <queue>
#include <vector>
#define VAL 100005

using namespace std;

ifstream fin("bfs.in");
ofstream fout("bfs.out");

int N, M, K, i, j;
int a, b, cost[VAL];
vector<int> v[VAL];
queue<int> q;

void bfs()
{
    q.push(K);
    while (q.empty()==false)
    {
        a=q.front();
        q.pop();
        for (i=0; i<v[a].size(); i++)
        {
            if (cost[v[a][i]]==-1)
            {
                cost[v[a][i]]=cost[a]+1;
                q.push(v[a][i]);
            }
            else
            {
                if (cost[v[a][i]]>cost[a]+1)
                {
                    cost[v[a][i]]=cost[a]+1;
                    q.push(v[a][i]);
                }
            }
        }
    }
}

int main()
{
    fin >> N >> M >> K;
    for (i=1; i<=M; i++)
    {
        fin >> a >> b;
        v[a].push_back(b);
    }
    for (i=1; i<=N; i++)
      cost[i]=-1;
    cost[K]=0;
    bfs();
    for (i=1; i<=N; i++)
      fout << cost[i] << " ";
    fin.close();
    fout.close();
    return 0;
}