Cod sursa(job #2511664)

Utilizator tomitza.1604Sacuiu TomaAndrei tomitza.1604 Data 19 decembrie 2019 15:56:55
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.9 kb
#include <iostream>
#include <fstream>

using namespace std;

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

const int N = 100001;
const int M = 1000001;
int n, m, s, nr, x, y;
int d[N], q[N], vf[2*M], lst[N], urm[2*M];

void add(int x, int y){
    vf[++nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void bfs(int x0)

{
    int st, dr;
    for(int i = 1; i <= n; i++)
    {
        d[i] = -1;
    }
    st = 0;
    dr = -1;
    q[++dr] = x0;
    d[x0] = 0;
    while(st <= dr){
        int x = q[st++];
        for(int p = lst[x]; p != 0; p = urm[p]){
            int y = vf[p];
            if(d[y] == -1){
                q[++dr] = y;
                d[y] = 1 + d[x];
            }
        }
    }
}

int main()
{
    in >> n >> m >> s;
    for(int i = 1; i <= m; i++){
        in >> x >> y;
        add(x, y);
    }
    bfs(s);
    for(int i=1; i<=n; i++){
        out << d[i] << ' ';
    }
    return 0;
}