Cod sursa(job #2974101)

Utilizator TanasaStefanTanasa Stefan TanasaStefan Data 3 februarie 2023 09:43:54
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.1 kb
#include <bits/stdc++.h>

using namespace std;

ifstream f("bfs.in");
ofstream g("bfs.out");

vector < int > v[100005];

queue < int > q;

int best[500005];

bool inq[500005];

const int inf = 2e9;

int n, m , s;

void Dijkstra(int nod)
{
    q.push(nod);
    inq[nod] = 1;
    best[nod] = 0;
    while(q.empty() == 0)
    {
         nod = q.front();

        q.pop();

        for (int i = 0 ; i < v[nod].size() ; i++)
        {
            int vecin = v[nod][i];
            if(best[nod] + 1 < best[vecin])
            {
                best[vecin] = best[nod] + 1;
                if(inq[vecin] == 0)
                    q.push(vecin);
            }
        }
    }
}
int main()
{
    f >> n >> m >> s;
    int x , y;

    for (int i = 1 ; i <= m ; i++)
        {
             f >> x >> y;
             v[x].push_back(y);
        }

    for (int i = 1 ; i <= n ; i++)
        best[i] = inf;

    best[s] = 0;

    Dijkstra(s);

    for ( int i = 1 ; i <= n ; i++)
        if(best[i] == inf)
        g << -1 << " ";
    else
        g << best[i] << " ";
}