Cod sursa(job #2581107)

Utilizator PetrescuAlexandru Petrescu Petrescu Data 14 martie 2020 15:55:42
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.27 kb
#include <bits/stdc++.h>
#define MAX 100000

using namespace std;

struct
{
    int nod;
    int nrArce;
}coada[MAX * 10 + 5];

int vizitat[MAX + 5], st, dr;
vector<int>graph[MAX + 5];

void bfs(int s, int nrArce = 0)
{
    int st, dr;

    st = dr = 0;
    coada[dr].nod = s;
    coada[dr].nrArce = nrArce;
    vizitat[s] = nrArce;

    while(st <= dr)
    {
        int nod = coada[st].nod;

        for(auto x : graph[nod])
            if(x == s)continue;
            else if(!vizitat[x])
            {
                dr++;
                coada[dr].nod = x;
                coada[dr].nrArce = coada[st].nrArce + 1;
                vizitat[x] = coada[dr].nrArce;
            }

        st++;
    }
}

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

    ios::sync_with_stdio(false);
    fin.tie(0);
    fout.tie(0);
    srand(time(NULL));

    int n, m, s;
    fin >> n >> m >> s;

    for(int i = 1; i <= m; i++)
    {
        int a, b;

        fin >> a >> b;

        graph[a].push_back(b);
    }

    bfs(s);

    for(int i = 1; i <= n; i++)
    {
        if(i != s && !vizitat[i])vizitat[i] = -1;

        fout << vizitat[i] << " ";
    }
    fin.close();
    fout.close();

    return 0;
}