Cod sursa(job #2509511)

Utilizator DanSDan Teodor Savastre DanS Data 14 decembrie 2019 12:06:00
Problema BFS - Parcurgere in latime Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.93 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 adauga(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];
                //pred[y] = x;
            }
        }
    }

}

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