Cod sursa(job #1992752)

Utilizator workwork work work Data 21 iunie 2017 12:38:50
Problema BFS - Parcurgere in latime Scor 20
Compilator cpp Status done
Runda Arhiva educationala Marime 0.79 kb
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

int n, m, s, lvl[100003], w[100003], x, y;
vector<int> v[100003];
queue<int> q;

void bfs()
{
    vector<int> :: iterator it;
    q.push(s);
    while(!q.empty())
    {
        x = q.front();
        w[x] = 1;
        q.pop();
        for(it = v[x].begin(); it != v[x].end(); ++ it)
            if(!w[*it]) q.push(*it), lvl[*it] = lvl[x] + 1;
    }
}

int main()
{
    F >> n >> m;
    F >> s;
    for(int i = 0; i < m; ++ i)
    {
        F >> x >> y;
        v[x].push_back(y);
    }
    for(int i = 1; i <= n; ++ i)
        lvl[i] = -1;
    lvl[s] = 0;
    bfs();
    for(int i = 1; i <= n; ++ i)
        G << lvl[i] << " ";
    return 0;
}