Cod sursa(job #1985213)

Utilizator Mihai_PredaPreda Mihai Dragos Mihai_Preda Data 27 mai 2017 10:04:34
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.12 kb
#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

const int nMax = 100005;
const int INF = (1 << 29);

int n, m, s;
vector<int> vecini[nMax];
int dp[nMax];

void citire()
{
    ifstream in("bfs.in");
    in >> n >> m >> s;
    int x, y;
    for(int i = 1; i <= m; ++i)
    {
        in >> x >> y;
        vecini[x].push_back(y);
    }
    in.close();
}

void BFS(int start)
{
    for(int i = 1; i <= n; ++i)
        dp[i] = INF;
    queue<int> q;
    q.push(start);
    dp[start] = 0;
    int p;
    while(q.empty() == false)
    {
        p = q.front();
        q.pop();

        for(auto v:vecini[p])
        {
            if(dp[v] == INF)
            {
                dp[v] = dp[p] + 1;
                q.push(v);
            }
        }
    }
}

void afisare()
{
    ofstream out("bfs.out");
    for(int i = 1; i <= n; ++i)
    {
        if(dp[i] == INF)
            out << -1 << " ";
        else
            out << dp[i] << " ";
    }
    out.close();
}

int main()
{
    citire();
    BFS(s);
    afisare();
    return 0;
}