Cod sursa(job #2920298)

Utilizator alexia._.fFlorete Alexia Maria alexia._.f Data 23 august 2022 15:38:34
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.34 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

const int N = 100005;

vector <int> muchii[N];
queue <int> coada;
int distanta[N];

void BFS()
{
    int nod, vecin;
    while(!coada.empty()) ///cat timp coada nu este goala
    {
        nod = coada.front(); ///extragem primul element din coada
        coada.pop(); ///il stergem din coada

        for(unsigned int i = 0; i < muchii[nod].size(); i++)
        {
            ///pentru fiecare element parcurgem vecinii
            vecin = muchii[nod][i];
            if(distanta[vecin] == -1) ///daca nu am fost acolo
            {
                coada.push(vecin);
                distanta[vecin] = distanta[nod] + 1; ///inaintam

            }
        }
    }
}

int main()
{
    int n, m, nod_start, x, y;

    in >> n >> m >> nod_start;

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

    for(int i = 1; i <= n; i++)
    {
        distanta[i] = -1;
    }
    distanta[nod_start] = 0; ///distanta la nodul de start este 0

    coada.push(nod_start); ///adugam in coada nodul de start

    BFS();

    for(int i = 1; i <= n; i++)
    {
        out << distanta[i] << " ";
    }

    in.close();
    out.close();
    return 0;
}